From looking at your first post, and reviewing the CPAN wiki page I suspect that the result you encountered is the result of the commands in one of these two sections of the wiki article:
1) Perl needs to know where the new modules are going to be installed:
$ export PERL5LIB
2) $ perl -MCPAN -e shell
Are you ready for manual configuration? yes
Policy on building prerequisites (follow, ask or ignore)? follow
Parameters for the 'perl Makefile.PL' command? Typical frequently used settings:
PREFIX=~/perl non-root users (please see manual for more hints)
Your choice: PREFIX=~/perlmods
I suspect that one of those command lines may have been mis-typed, omitted, or entered with an incorrect path, but of course, I don't know for sure.
I suggest you delete all the created directories/files from your failed attempt, and try it again with special attention to the above section values. The methodology as described does work, though it can be tricky.
Additionally, make sure that the module you are trying to install is not already part of the Perl installation at DH, and that you completed the "use lib '/home/username/perlmods/share/perl/5.8.4/';" step.
What module(s) are you trying to install?