I suggest you start by opening a new directory for downloading.
$mkdir per4lib
download module from CPAN and save it in directory per4lib become superuser
/#tar -zxvf perl-module.tar.gz this will extract the download and build a directory
/#cd new-directory-name /#perl Makefile.PL /#make /#make install
If I remenber correctly there are a couple of dependencies for marc2xml. Watch the result of the Makefile.PL. The dependencies are loaded using the same method above. You are finished.