The undump program comes from the TeX distribution. If you have TeX, then you may have a working undump. If you don't, and you can't get one, AND you have a GNU emacs working on your machine that can clone itself, then you might try taking its unexec() function and compiling Perl with -DUNEXEC, which will make Perl call unexec() instead of abort(). You'll have to add unexec.o to the objects line in the Makefile. If you succeed, post to comp.lang.perl.misc about your experience so others can benefit from it.
If you have a version of undump that works with Perl, please submit its anon-FTP whereabouts to the FAQ maintainer.
Other resources at this site: