Natbib does not display full author name

I can't get natbib to display the full author name. Instead, I only get the last character. My document looks like so:

\documentclass[a4paper,10pt]{article}
\usepackage[sort, comma]{natbib}
\begin{document}
\section{Introduction}

According to \citet{Farmer2004}...

\bibliographystyle{plainnat}
\bibliography{./refs}
\end{document}

The output of this is

According to r (a)

I am running Kile on Ubuntu 10.04, and my build order is PDFLatex, BibTex, PDFLatex,PDFLatex. I also tried building with TeXworks on both Ubuntu and Windows 7, result is identical. If I comment out natbib and use \cite instead of \citet, the output is

According to [Farmer(2004)]

The bib file looks like so:

\bibitem[Farmer(开发者_运维知识库2004)]{Farmer2004}
Charles Farmer.
\newblock {Effect of electronic stability control on automobile crash risk.}
\newblock \emph{Traffic injury prevention}, 5\penalty0 (4):\penalty0 317--25,
  December 2004.

and the .aux file looks like so:

\relax 
\citation{Farmer2004}
\citation{Tseng1999}
\citation{Farmer2004}
\select@language{english}
\@writefile{toc}{\select@language{english}}
\@writefile{lof}{\select@language{english}}
\@writefile{lot}{\select@language{english}}
\@writefile{toc}{\contentsline {section}{\numberline {1}Introduction}{1}}
\newlabel{sec:intro}{{1}{1}}
...
\bibcite{Farmer2004}{Farmer(2004)}

...and some more citations below... \newblock ISSN 1538-9588. \newblock \doi{10.1080/15389580490896951}. \newblock URL \url{http://www.ncbi.nlm.nih.gov/pubmed/15545069}.

Any suggestions are highly appreciated.

I guess you didn't include the information that you use newclude, because I ran into this error today with newclude and natbib

the answer is include newclude before natbib, then it works (for me)

\usepackage{newclude} \usepackage{natbib}

Thanks everyone for your help. In case someone else stumbles upon this question, the answer is "do not use package newclude".