Undefined Control Sequence Error in PDFLatex with \includegraphics

Question

I receive two errors when using \includegraphics command in pdflatex. I've never seen these particular errors discussed/answered before.

I have the following MWE (this is all I have in the document so far):

\documentclass{article}

\usepackage{graphicx}

\begin{document}

\begin{figure}
\begin{center}
\includegraphics[scale=0.92]{box.png}
\hspace{0.5in}\parbox{6in}{\caption{Box comparing two methods \label{box}}} 
\end{center} 
\end{figure}

\end{document}

where box is the figure to be included. There are two errors produced. Both of them say the following:

! Undefined control sequence.

recently read \ltx@zapspace

I do not know what these errors mean. I assume they have something to do with \ltx@zapspace. I appreciate any help or clarification of this error or how to correct it.

Answer 1

Driver file pdftex.def uses package ltxcmds since version 2011/04/21 v0.06:

 \RequirePackage{ltxcmds}[2010/12/07]

Macro \ltx@zapspace is provided by package ltxcmds since this version 2010/12/07 v1.14.

Thus very likely an outdated package is the cause and LaTeX throws a warning, e.g.:

LaTeX Warning: You have requested, on input line 408, version
               `2010/12/07' of package ltxcmds,
               but only version
               `2009/08/05 v1.0 LaTeX kernel commands for general use (HO)'
               is available.

Solution: update at least package ltxcmds, better the whole bundle oberdiek.