Update: I fixed a typo. But more importantly, I realized from the latter responses that I was over complicating. Using an unless block to do the error-checking is much easier and more efficient than the eval.
How about:

eval {
   $newSeriesSth->execute() || die $newSeriesStr->exrrstr;
};

if ($@) {
  if ($@ =~ /duplicate/) {
     print "Trying to insert duplicate row.\n";
  } else {
     die "Unhandled errer. DBI says: $DBI::errstr";
  }
}
[download]

Or you could try one of the various throw/catch implementations on cpan. (Or wait for Perl6 with built in exception support.)

-pete
"Pain heals. Chicks dig scars. Glory lasts forever."