[Tex/LaTex] Undefined control sequence \begin{abstract} but abstract appears

abstractdocument-classes

I'm using a customised (not by me) document class called geogthesis to produce my Geography PhD thesis.

When I compile the file I get an error saying:

Undefined control sequence. [\begin{abstract}]

However, the PDF actually builds fine, and includes the abstract – which is strange. Still, I'd like to get rid of the error (errors when building my thesis scare me!)

I'm using the LaTeX file below, combined with the geogthesis.cls file:

\RequirePackage{ifpdf}
\documentclass{geogthesis}

\begin{document}
\frontmatter
\title      {TITLE HERE}
\authors    {\texorpdfstring{\href{mailto:r.t.wilson@soton.ac.uk}{Robin Wilson}}{}}
\supervisor {\texorpdfstring {\href{mailto:blah@soton.ac.uk}{Blah}}{}}
\cosupervisor {\texorpdfstring {\href{mailto:blah@soton.ac.uk}{Blah}}{}}
\addresses  {\deptname\\\univname}
\date       {\today}
\subject    {Remote Sensing}
\keywords   {keywords}
\maketitle

\begin{abstract}
\small{Blah blah}
\end{abstract}

\mainmatter


Main text here!

\end{document}

Best Answer

Remember `\small does not take arguments.

There is at least one error in that class.

\makeatletter
\renewenvironment{abstract}
{
\btypeout{Abstract Page}
\thispagestyle{empty}
\null\vfil
\begin{center}
\setlength{\parskip}{0pt}
{\normalsize \UNIVNAME \par}
{\normalsize {ABSTRACT} \par}
\medskip
{\normalsize \FACNAME \par}
{\normalsize \DEPTNAME \par}
\medskip
{\large Doctor of Philosophy (PhD)\par}
\medskip % <-- typo said \medsckip
{\normalsize\bf \@title \par}
\medskip
{\normalsize by \authornames \par}
\medskip
\end{center}
}
{
\vfil\vfil\vfil\null
\cleardoublepage
}

\makeatother