[pdftex] "fi" can not be copied correctly in a pdf generated by pdflatex

[Peng Yu]

Hi,

I run pdflatex on the following tex file. In the generated pdf file,
"fi" can not be copied correctly (from say, acrobat). I then tried
latex->dvipdf, and I can copy "fi" from the pdf file generated in this
way. Does anybody know what is the problem with pdflatex. How to make
pdflatex generated pdf so that "fi" is copiable?

\documentclass{report}
\begin{document}
Definition
\end{document}


My OS is Mac OX 10.6.7. pdflatex is installed here. But I don't
remember how it was installed.

/usr/local/texlive/2010/bin/x86_64-darwin/pdflatex


-- 
Regards,
Peng