title: Undefined control sequence at first line of a document
body: <pre><code>\documentclass{book}
  
  \usepackage{amsmath}
  \usepackage[german]{babel}
  \usepackage{amssymb}
  \usepackage{amsxtra}
  \usepackage[dvips]{epsfig,psfrag}
  \usepackage{listings}
  
  \newcommand{\refchapter}[1]{Kapitel~\ref{#1}}
  \newcommand{\refsec}[1]{Sektion~\ref{#1}}
  \newcommand{\refeqn}[1]{Gleichung~(\ref{#1})}
  \newcommand{\reffig}[1]{Abbildung~\ref{#1}}
  
  \title{\bf Grundz\"uge der Softwareentwicklung \\
  {\small Analyse- und Entwurfsdokument} \vspace{1cm}\\
  \centering
  \epsfig{file=figures/logo.eps,width=.4\textwidth}
  }
  
  \author{Uschi Musterfrau, Detlef Mustermann und Ralf Auchmustermann}
  \date{Matr.-Nr. 0815, 0816 und 0817 \\
  email: {\tt [uschi|detlef|ralf]@rwth-aachen.de} 
  }
  
  \begin{document}
  
  \lstloadlanguages{[ISO]C++}
  \lstset{basicstyle=\small, numbers=left, numberstyle=\footnotesize,
    stepnumber=1, numbersep=5pt, breaklines=true, escapeinside={/*@}{@*/}}
  
  
  \pagestyle{headings}
  
  \maketitle
  
  \tableofcontents
  
  \include{vorwort}
  \include{analyse}
  \include{entwurf}
  \include{nutzerdoc}
  \include{entwicklerdoc}
  
  \bibliographystyle{plain}
  \bibliography{analyse_entwurf}
  
  \appendix
  
  \include{quellcode}
  
  
  \end{document}
  </code></pre>
  
  <p>this is how my file starts. I didn't even edit it, I received it like this. However, if I want to make a pdf, it gives me the undefined control sequence error at the first line... What is wrong??</p>