Net::LDAP is pure perl and IMHO the best way to talk LDAP. But it's based on Convert::ASN1 which uses XS (=C-Code), so Convert::ASN1 needs a C compiler...

you can download both packages from http://search.cpan.org/ . If you read the README or INSTALL, it tells you how to install it.

I don't know if there exist prebuild packages for AIX