Not much we can do about that until the software is radically rewritten to use a proper database - it has to trundle off through (currently) 40000 files, and thats something Linux can't do very well.
Is that why the "normal" search button is limited to 25 posts?
Your using a flat-file backend for Yabb?? Thought it did MySQL...
[edit]actually, jsut read up on Yabb... previously used SMF myself which had SQL support (also based on YaBB), thought YaBB had it too but I guess not...
also... if your running YaBB in a linux VM which you always hate... how come you aren't running it natively under IIS/Windoze (which it says it works under?)[/edit]
ActivePerl is rubbish.
Used to look after some web/sql servers for a major UK airline. Their booking system was written by a company that would only support the freeware Activeperl, and not the commercial version. Needless to say, that site was often on its back.
If you want to run Unix technologies, such as perl, php and so on, run it on Unix (or Linux if you can't run proper Unix).