I had a big problem installing Tk on Red Hat 9, and some googling turned up info on RH9's default locale, Perl, and why they don't mix sometimes.
The short version of the story is this: if you're using Linux, and if your problem is the same one I had, try checking the locale with echo $LANG at a command line. If the locale ends with UTF-8 (mine is en_US.UTF-8), change the locale to the non-UTF version (e.g. export LANG=en_US) and try installing it again.
Also, let me know if it works for you. It's a long shot, but this could be the first time I've ever had the right answer to anything.