Question on possible effects of mod_perl on mod_cgi

[Terra Info]

I am debugging a particularly nasty issue right now on a perl script that when written 2+ yrs ago worked fine. NB: It does not run under mod_perl and it has not been modified since then. I run it from the cmd line (with the identical query string and all referenced %ENV vars set identical as well) and it runs fine. I run it as a typical CGI and it has problems that, in *some* ways, mirror the behavior of a poorly written (symptoms associated with unscoped globals, etc;) perl app under mod_perl. And since this is a poorly written app I am curious. Is there any link between mod_perl (1.99..) and mod_cgi (Apache 2)? Does mod_perl in anyway influence or maybe cause PerlRun like caching under mod_cgi? I am just trying to eliminate all possibilities as this one has been a real PITFA.
Thanks,
Tom