[Koha] I need to add a path to @INC for KOHA, how?

Hi all, I am in the process of installing KOHA on a Debian Sarge system, and I am kind of stuck. I need to add the path /usr/local/koha/intranet/modules/C4 to @INC, perl complians that it cannot find this path, and rightly so, because it is not in @INC I found http://www.perl.com/pub/a/2002/05/14/mod_perl.html?page=2, with some helpful information, but it does not solve my problem, I keep getting errors. Maybe I missed something? (Like when I found out you need SetEnvIf in Debian instead of SetEnv) I know hardly anything about perl, so please be patient (and descriptive) and if someone can show some examples it would be most welcome... Thanks! Marty Jongepier