Without any more specific code samples you're probably just going to get generalities and hints (like this . . .).

Normal Perl code shouldn't be generating bus errors. The most likely culprit is a buggy XS extension, or an XS extension that's being passed "bad" data that it's not validating. Check that you're checking the return values from things like module initialization calls (e.g. maybe you're getting an error when you attempt to open the database (hand waving here because I've never used the module in question) but you don't catch that and pass an invalid handle to a query routine; or maybe you're getting an error back from one of your lookups and there's something that needs to be done to put the handle back into a "sane" state before you continue making queries).