DProf is known to have segfault issues, I asked about it awhile back somewhere around here (UPDATE: Devel::Dprof and heisencores). I also mailed perl5-porters(UPDATE:archive) who confirmed it, come to think of I should have followed up on that thread. Generally it just takes a few tries to get it to work.

--
perl -pe "s/\b;([st])/'\1/mg"