I guess that it's the $app->log($FATAL...) bit that causes the script to exit.

You could probably do something like this:

foreach ....( ... )
{
    my $rc = $dbh->do($sql);
    if(!$rc) {
        if($dbh->err == 4305) {
            # print a warning here?
            last;
        } else {
            $app->log(...);
        }
    }
}
...
[download]

Michael