kcalvelli,
I might be able to make this easy for you. The system AIX Perl is built with the non-free propietary IBM compiler. As a result, you can not use any non pure Perl modules because they will not be binary compatible unless they have an expensive license. Update: Let me give a concrete example. Let's say they want to connect to a database (DB2, Oracle, Pg, etc). You can't build DBD::DB2 with gcc and have it work with the system Perl.