------------- EXCEPTION -------------
MSG: Need to have installed XML::Twig
STACK Bio::DB::Taxonomy::entrez::get_taxon /Library/Perl/5.8.8/Bio/DB/Taxonomy/entrez.pm:195
STACK toplevel Main_Update.pl:711
-------------------------------------

originating from these two lines.

710: my $entrez_dbh = Bio::DB::Taxonomy::entrez->new();
711: my $taxon_info = $entrez_dbh->get_taxon(-gi => $protein_gi_w_prot_acc{$target_prot_acc}, -db => 'protein'  );