In ppm4, which is included in the latest ActivePerl release (build 819), you can set up and install to areas other than
C:\Perl and
C:\Perl\site; from the docs:
PPM allows for the addition of new install areas, which is useful for shared ActivePerl installations where the user does not have write permissions for the site and perl areas. New install areas are added by simply setting up new library directories for perl to search, and PPM will set up install areas to match. The easiest way to add library directories for perl is to specify them in the PERL5LIB environment variable, see the perlrun manpage for details. PPM will create etc, bin, html directories as needed when installing packages.