Here is some reading they should be helpful. DBI can be tough on memory so check this article out. Also this article although it deals with mod_perl it has some good info on Perl memory usuage in general.

Finally,If you haven't already done so, check out perldebguts debugging memory section.

mitd-Made in the Dark
'Interactive! Paper tape is interactive!
If you don't believe me I can show you my paper cut scars!'