title: Wrong chapter number on page headers except first page
body: <p>I am writing up my thesis in Latex and have a template. It works nicely for every thing else except one. Chapter numbers are correctly incremented on the first page of each chapter but for consecutive pages of each chapter, the header saying "Chapter x - This is a chapter title" have 1 always as chapter number.</p>
  
  <p>Following is the code sample from the CLS file which i think is relevant to the headers:</p>
  
  <pre><code>\newcommand\btypeout[1]{\bhrule\typeout{\space #1}\bhrule}
  \def\today{\ifcase\month\or
    January\or February\or March\or April\or May\or June\or
    July\or August\or September\or October\or November\or December\fi
    \space \number\year}
  \usepackage{setspace}
  \onehalfspacing
  \setlength{\parindent}{0pt}
  \setlength{\parskip}{2.0ex plus0.5ex minus0.2ex}
  \usepackage{vmargin}
  \setmarginsrb           { 1.5in}  % left margin
                          { 0.6in}  % top margin
                          { 1.0in}  % right margin
                          { 0.8in}  % bottom margin
                          {  20pt}  % head height
                          {0.25in}  % head sep
                          {   9pt}  % foot height
                          { 0.3in}  % foot sep
  \raggedbottom
  \setlength{\topskip}{1\topskip \@plus 5\p@}
  \doublehyphendemerits=10000       % No consecutive line hyphens.
  \brokenpenalty=10000              % No broken words across columns/pages.
  \widowpenalty=9999                % Almost no widows at bottom of page.
  \clubpenalty=9999                 % Almost no orphans at top of page.
  \interfootnotelinepenalty=9999    % Almost never break footnotes.
  \usepackage{fancyhdr}
  \lhead[\rm\thepage]{\fancyplain{}{\sl{\rightmark}}}
  \rhead[\fancyplain{}{\sl{\leftmark}}]{\rm\thepage}
  \chead{}\lfoot{}\rfoot{}\cfoot{}
  \pagestyle{fancy}
  
  %% Chapter Heading ---------------
  \renewcommand{\chaptermark}[1]{\btypeout{\thechapter\space #1}\markboth{\@chapapp\ \thechapter\ #1}{\@chapapp\ \thechapter\ #1}}
  
  %%--------------------------------------------------
  \renewcommand{\sectionmark}[1]{}
  \renewcommand{\subsectionmark}[1]{}
  \def\cleardoublepage{\clearpage\if@twoside \ifodd\c@page\else
  \hbox{}
  \thispagestyle{empty}
  \newpage
  \if@twocolumn\hbox{}\newpage\fi\fi\fi}
  </code></pre>