On my Microsoft Access database the following works:

#Check for duplicate insert into database.
if ($dbh->errstr()=~/SQL-23000/)
    {
    $template->param(duplicate => 1);
    }
[download]

If during debug, you set $dbh->{RaiseError} =1, your logs will show what errstr MySQL is throwing... checking for that (instead of SQL-23000 as in my case) should fix this issue...

2005-10-01 Retitled by Chady, as per Monastery guidelines