"Undefined Control Sequence" but compiles fine? Using custom class

Question

I am implementing a custom document class for my PhD dissertation. In it, I have clearly defined certain commands, e.g. \maketitle (renewed command) and \makeapproval. When I try to compile my main thesis document, I receive errors saying "Undefined control sequence. \maketitle" or "Undefined... \makeapproval". However when I check the generated PDF file, everything seems to be okay, which is weird.

What's going on? How can I correct these innocuous error messages?

I'm running on Ubuntu 20.04.4 LTS. The output of pdftex --version is:

pdfTeX 3.14159265-2.6-1.40.20 (TeX Live 2019/Debian)

Here is a minimal working example of my thesis tex file test.tex:

    \documentclass[phd,bottom,sig]{usbthesis2}
    \author{arturodonjuan}
    \title{A Dissertation Title}
    
    \begin{document}
        \maketitle %
        \makeapproval % 
    \end{document}

with the accompanying class file usbthesis2.cls:

    \NeedsTeXFormat{LaTeX2e}
    \ProvidesClass{usbthesis2}[Bing Bong thesis class]
    
    \newif\if@top
    \newif\if@sig
    
    \DeclareOption{master}{%
        \newcommand{\@work}{Thesis}%
        \newcommand{\@degree}{Master of Science}}
    \DeclareOption{phd}{%
        \newcommand{\@work}{Dissertation}%
        \newcommand{\@degree}{Doctor of Philosophy}}
    \DeclareOption{top}{\@toptrue}
    \DeclareOption{bottom}{\@topfalse}
    \DeclareOption{sig}{\@sigtrue}
    \DeclareOption{nosig}{\@sigfalse}
    \DeclareOption*{\PackageWarning{usbthesis2}{This package does not 
            recognize option: \CurrentOption}}
    %\ExecuteOptions{phd,bottom}
    \ProcessOptions\relax
    
    \LoadClass[letterpaper,12pt,oneside]{report}
    
    \RequirePackage{setspace}
    \doublespacing
    \RequirePackage{vmargin}
    \setpapersize{USletter}
    
    %\setmargins{1.5in}{1.25in}{5.5in}{8.125in}{0.125in}{0.75in}{0.125in}{0.325in}
    %\setmargins{1.5in}{1.25in}{5.5in}{8.125in}{0.125in}{0.2in}{0.125in}{0.5in}
    
    \if@top
    \setmarginsrb{1.5in}{1in}{1.5in}{1in}{0.125in}{0.75in}{0.125in}{0.325in}
    \else
    \setmarginsrb{1.5in}{1in}{1.5in}{1in}{0.125in}{0.2in}{0.125in}{0.5in}
    \fi
    
    %\renewcommand{\LARGE}{\Large}
    %\renewcommand{\huge}{\Large}
    %\renewcommand{\Huge}{\LARGE}
    %\renewcommand{\Huge}{\Large}
    
    \newcommand{\ps@prelim}{%
        \pagenumbering{roman}%
        \renewcommand{\@oddhead}{}%
        \renewcommand{\@evenhead}{}%
        \renewcommand{\@evenfoot}{\hfil\textrm{\thepage}\hfil}%
        \renewcommand{\@oddfoot}{\@evenfoot}}
    \newcommand{\ps@thesis}{%
        \pagenumbering{arabic}%
        \if@top
        \renewcommand{\@oddfoot}{}%
        \renewcommand{\@evenfoot}{}%
        \renewcommand{\@evenhead}{\hskip-0.25in \textrm{\thepage}\hfil}%
        \renewcommand{\@oddhead}{\hfil \textrm{\thepage} \hskip-0.25in}%
        \renewcommand{\ps@plain}{%
            \renewcommand{\@oddfoot}{}%
            \renewcommand{\@evenfoot}{}%
            \renewcommand{\@evenhead}{\hskip-0.25in \textrm{\thepage}\hfil}%
            \renewcommand{\@oddhead}{\hfil\textrm{\thepage} \hskip-0.25in}}
        \fi
    }
    
    \renewcommand{\month}[1]{\newcommand{\@month}{#1}}
    \renewcommand{\year}[1]{\newcommand{\@year}{#1}}
    
    \newcommand{\program}[1]{%
        \newcommand{\@program}{#1}}
    \newcommand{\director}[2]{%
        \newcommand{\@directorname}{#1}%
        \newcommand{\@directorposition}{#2}}
    \newcommand{\chairman}[2]{%
        \newcommand{\@chairmanname}{#1}%
        \newcommand{\@chairmanposition}{#2}}
    \newcommand{\fstmember}[2]{%
        \newcommand{\@fstmembername}{#1}%
        \newcommand{\@fstmemberposition}{#2}}
    \newcommand{\sndmember}[2]{%
        \newcommand{\@sndmembername}{#1}%
        \newcommand{\@sndmemberposition}{#2}}
    \newcommand{\trdmember}[2]{%
        \newcommand{\@trdmembername}{#1}%
        \newcommand{\@trdmemberposition}{#2}}
    \newcommand{\outmember}[3]{%
        \newcommand{\@outmembername}{#1}%
        \newcommand{\@outmemberposition}{#2}%
        \newcommand{\@outmemberschool}{#3}}
    \newcommand{\dean}[1]{%
        \newcommand{\@dean}{#1}}
    
    \renewcommand{\maketitle}{\begin{titlepage}%
            \if@top
            \setmarginsrb{1.5in}{1in}{1.5in}{1in}{0.125in}{0.2in}{0.125in}{0.5in}
            \fi
            \renewcommand{\footnotesize}{\small} %\let\footnoterule\relax
            \setcounter{page}{0}%
            \begin{center}%
                \setlength{\baselineskip}{29pt}%
                %     \vspace*{0.2in}%
                {\LARGE\textbf{\@title}}\\%
                
                \vfill 
                \setlength{\baselineskip}{14.5pt}
                %     \large
                %     [0.2in] 
                A \@work\ Presented\\%
                %     [0.2in] \vfill A \@work, Presented\\%
                [0.2in] by\\%
                [0.25in] \textbf{\large \@author} \\%
                [0.25in] to\\%
                [0.2in] The Graduate School\\%
                [0.2in] in Partial Fulfillment of the Requirements\\
                %     [0.2in] Requirements\\%
                [0.2in] for the Degree of\\%
                [0.5in] \textbf{\large \@degree}\\%
                [0.2in] in\\%
                [0.2in] \textbf{\large \@program}\\%
                [0.5in] Bing Bong University\\%
                [0.2in] \@month\ \@year%
            \end{center}%
            \par\null%
            \setcounter{footnote}{0}%
            \let\thanks\relax%
            \let\maketitle\relax%
    \end{titlepage}}
    
    \newcommand{\makeapproval}{%
        \if@top
        \setmarginsrb{1.5in}{1in}{1.5in}{1in}{0.125in}{0.2in}{0.125in}{0.5in}
        \fi
        \pagestyle{prelim}
        \setcounter{page}{2}%
        \begin{center}%
            \setlength{\baselineskip}{14.5pt}%
            \textbf{Bing Bong University}\\%
            [0.1in]{The Graduate School} \\%
            [0.35in] \textbf{\large \@author}%
        \end{center}%
        \vspace{0.25in}%
        {\setlength{\baselineskip}{14.5pt}%
            We, the \MakeLowercase{\@work}\ committee for the above candidate for the
            \@degree\ degree, hereby recommend acceptance of this \MakeLowercase{\@work}.\par}
        \begin{center}%
            \setlength{\baselineskip}{14.5pt}%
            
            \rule[-0.55in]{3in}{\if@sig 0.01in \else 0.00in \fi}\\
            [0.03in]\textbf{\@directorname{} -- \@work{} Advisor\\
                \@directorposition}\\%
            
            \rule[-0.55in]{3in}{\if@sig 0.01in \else 0.00in \fi}\\
            [0.03in]\textbf{\@chairmanname{} -- Chairperson of Defense\\
                \@chairmanposition}\\%
            
            \rule[-0.55in]{3in}{\if@sig 0.01in \else 0.00in \fi}\\
            [0.03in]\textbf{\@fstmembername\\
                \@fstmemberposition}\\%
            
            \rule[-0.55in]{3in}{\if@sig 0.01in \else 0.00in \fi}\\
            [0.03in]\textbf{\@outmembername\\
                \@outmemberposition\\
                \@outmemberschool}
        \end{center}%
        
        \vspace{0.2in}%
        \begin{center}%
            This \MakeLowercase{\@work}\ is accepted by the Graduate School.
            \parbox{\if@sig 3in \else 2.5in \fi}%
            {\centering%\raggedright%
                \baselineskip 14.5pt%
                \rule[-0.55in]{3in}{\if@sig 0.01in \else 0.00in \fi}\\[0.03in]
                \if@sig \else \@dean\\ \fi
                Dean of the Graduate School\\}%
        \end{center}\clearpage}
    
    \renewenvironment{abstract}{%
        \if@top
        \setmarginsrb{1.5in}{1in}{1.5in}{1in}{0.125in}{0.2in}{0.125in}{0.5in}
        \fi
        \begin{center}%
            \setlength{\baselineskip}{14.5pt}%
            \vspace*{0.1in}%
            {\large Abstract of the \@work}\\%
            [0.2in]{\textbf{\Large{\@title}}}\\%
            %    [0.2in]{\Huge{\@title}}\\%
            %    {\bf \sc \Huge {\@title\\}}%
            \vspace{0.2in} by \\%
            %    [0.2in]by\\%
            [0.2in]\textbf{\large \@author}\\%
            [0.3in]\textbf{\large \@degree}\\%
            [0.2in]in\\%
            [0.2in]\textbf{\large \@program}\\%
            [0.2in]{\large Bing Bong University} \\
            [0.2in]{\large \@year}\\%
            [0.2in]\if@sig {\large \@directorname} \fi %for extra abstract copy
        \end{center}%
        \par%
        \vspace{0.4in}%
        \begin{quote}}%
        {\end{quote}%
        %\par\vfil\null
        \clearpage}
    
    
    \newenvironment{dedication}{%
        \if@top
        \setmarginsrb{1.5in}{1in}{1.5in}{1in}{0.125in}{0.2in}{0.125in}{0.5in}
        \fi
        \thispagestyle{empty}%
        \pagestyle{empty}
        \vspace*{\fill}%
        \begin{center}}%
        {\end{center}\vspace*{\fill}\clearpage}
    
    \newenvironment{acknowledgements}{%
        \if@top
        \setmarginsrb{1.5in}{1in}{1.5in}{1in}{0.125in}{0.2in}{0.125in}{0.5in}
        \fi
        \clearpage%
        \phantomsection
        \addcontentsline{toc}{chapter}{\protect\numberline{}{Acknowledgements}}
        \chapter*{Acknowledgements}%
        \thispagestyle{empty}%
        \pagestyle{empty}}%
    {\clearpage}
    
    \renewenvironment{thebibliography}[1]
    {\chapter*{\bibname
            \@mkboth{\MakeUppercase\bibname}{\MakeUppercase\bibname}}%
        \list{\@biblabel{\@arabic\c@enumiv}}%
        {\settowidth\labelwidth{\@biblabel{#1}}%
            \leftmargin\labelwidth
            \advance\leftmargin\labelsep
            \@openbib@code
            \usecounter{enumiv}%
            \let\p@enumiv\@empty
            \renewcommand\theenumiv{\@arabic\c@enumiv}}%
        \sloppy
        \clubpenalty4000
        \@clubpenalty \clubpenalty
        \widowpenalty4000%
        \sfcode`\.\@m}
    {\def\@noitemerr
        {\@latex@warning{Empty `thebibliography' environment}}%
        \endlist
        \addcontentsline{toc}{chapter}{\protect\numberline{}{\bibname
                \@mkboth{\MakeUppercase\bibname}{\MakeUppercase\bibname}}}}
    
    \renewcommand\listoffigures{%
        \if@top
        \setmarginsrb{1.5in}{1in}{1.5in}{1in}{0.125in}{0.2in}{0.125in}{0.5in}
        \fi
        \if@twocolumn
        \@restonecoltrue\onecolumn
        \else
        \@restonecolfalse
        \fi
        \clearpage
        \phantomsection
        \addcontentsline{toc}{chapter}{\protect\numberline{}{\listfigurename
                \@mkboth{\MakeUppercase\listfigurename}{\MakeUppercase\listfigurename}}}%
        \chapter*{\listfigurename
            \@mkboth{\MakeUppercase\listfigurename}%
            {\MakeUppercase\listfigurename}}%
        \@starttoc{lof}%
        \if@restonecol\twocolumn\fi
    }
    
    \renewcommand\listoftables{%
        \if@top
        \setmarginsrb{1.5in}{1in}{1.5in}{1in}{0.125in}{0.2in}{0.125in}{0.5in}
        \fi
        \if@twocolumn
        \@restonecoltrue\onecolumn
        \else
        \@restonecolfalse
        \fi
        \clearpage
        \phantomsection
        \addcontentsline{toc}{chapter}{\protect\numberline{}{\listtablename
                \@mkboth{\MakeUppercase\listtablename}{\MakeUppercase\listtablename}}}%
        \chapter*{\listtablename
            \@mkboth{%
                \MakeUppercase\listtablename}{\MakeUppercase\listtablename}}%
        \@starttoc{lot}%
        \if@restonecol\twocolumn\fi
    }

Answer 1

In the case of this particular document class, there are several commands you need to use in order to provide the information it needs in order to typeset the title page and approval page. Make sure you've added the following to your preamble:

\author{Author's Name}
\title{A Dissertation Title}
\program{Some program}
\month{June}
\year{2022}
\director{Someone}{Position1}
\chairman{Somebody}{Position2}
\fstmember{Someone else}{Position3}
\outmember{Member1}{Member2}{Member3}

There are some other fields not needed for those commands but might be needed elsewhere:

\sndmember{Someone}{Position4}
\trdmember{Someone}{Position5}
\dean{Dean's Name}