... or simply surround the DBI calls with eval()..

   my $dbh;
   eval {
      ## bunch of dbi calls..
      $dbh = DBI->connect( ... );
      $dbh->do( blah );
      $dbh->commit;
      $dbh->disconnect;
   };
   if( my $err = $@ ) {
       eval{ $dbh->rollback };
       eval{ $dbh->disconnect };
       ## print header, html, and $err
       exit 1; # or return, whatever
   }
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