Update your pg directory to the rel-2-4-patches release
cvs update -r rel-2-4-patches -dP
You are seeing a "bug" that occurs when you use perl 5.10 -- perl 5.10
does stricter testing than perl 5.8.x (see earlier postings to this forum)
I'd recommend doing the same update for webwork2 as well.
The rel-2-4-patches branch will have stable updates.
Hope this resolves all your problems -- it will certainly help.