Beamer error message: Undefined control sequence \Geom@lmargin [closed]

Question

I am running the following minimal example with beamer (windows 7, Miktex 2.9, all packages updated)

\documentclass{beamer}
\mode<presentation> {\usetheme{Darmstadt}}
\title{Fundamentals of Beamer}
\author{Author}
\institute{Department of Math, Main University}
\date{\today}

\begin{document}

\begin{frame}[t]
  \titlepage
\end{frame}

\begin{frame}[t]{Outline}
  \tableofcontents
\end{frame}

\section{Basics of Beamer}

\subsection{The Basics}

\begin{frame}[t]{The main Ideas of Beamer}
  Blah Blah....
  \begin{theorem}[\textbf{fancy}]
  This Theorem is very fancy.
  \end{theorem}
Blah Blah....
\end{frame}

\end{document}

I get the following error message repeatedly:

! Undefined control sequence.
\Gm@lmargin ->\Geom@lmargin 

l.8 \begin{document}

? 
! Missing number, treated as zero.
<to be read again> 
                   \hbox 
l.8 \begin{document}

? 
! Illegal unit of measure (pt inserted).
<to be read again> 
                   \hbox 
l.8 \begin{document}

? 

I am wondering what might be wrong.