"Carp.pm" ne "Carp/Heavy.pm".

Your version of bugzilla seems to expect a different version of Carp.pm that contains shortmess_heavy(). The current one (1.25) does have this function. Do you need to upgrade Perl? Post the output of "perl -V" (uppercase V!) and "perl -MCarp -e 'print $Carp::VERSION'" (if you use Windows, use "perl -MCarp -e "print $Carp::VERSION"" instead). Also, report the bugzilla version you attempt to use.

Alexander