I confess that I don't use mod_perl much, but the magic voodoo that you probably need here is the Apache directive:   SetEnv PERL5LIB path:path:path

As you may or may not know, @INC is the list of places that Perl will search when looking to find any library. You can see this list by entering perl -V (note the upper-case 'V'). This list is searched from front-to-back.

Many things can “prepend” entries to this list (that is to say, “add them to the front of it”):

• use lib pragmas.
• PERL5LIB and various other “environment variables.”
• Your own program-voodoo:   @INC is just an ordinary list...

By using this directive in Apache, you specify these environment-variable settings in the context of this <VirtualHost>. (You can probably use them in an .htaccess file, too.)

The value of this environment-variable is a list of path-names separated by colons. I always use absolute path-names.

One interesting bit of woot-woot! voodoo is the module FindBin, which can be used with use lib in the manner described in perldoc FindBin