I don't know much about solaris, but it seems to me you have the DB_File module installed in /bld/RT/Packages/Perl/perl-5.8.4/ext/DB_File/ while your @INC does not contain /bld/RT/Packages/Perl/perl-5.8.4/ext/DB_File/

If that is correct, you have 2 options here:

1. You install DB_File.pm in some directory that is in your standard @INC. - Preferable with a fresh install of DB_file from CPAN.
2. Or you can add /bld/RT/Packages/Perl/perl-5.8.4/ext/DB_File/ to @INC manually. Try doing

   export PERL5LIB=$PERL5LIB:/bld/RT/Packages/Perl/perl-5.8.4/ext/DB_File
   [download]

   before installing Apache::Session.