Underscore in URL using hyperref

[Sebastian Rahtz]

owner-pdftex at tug.org writes:
 > I cannot write URLs that have underscores in them.
 > 
 > This is what pdflatex says:
 > 
 > ! Undefined control sequence.
 > <argument> ...al \let \OT1\textunderscore
 >                                           \unhbox \voidb at x \kern .06e...
 > l.10 {\altavista's crawler}
 >                            ,  called the \emph{Scooter}, runs on a 1....
 > 
 > My source was:
 > 
I would guess this results from a fairly ancient LaTeX, in lieu of any
more detailed version information.

sebastian