Suppressing DBD Error messages

[gohaku]

Hi everyone,
I'm sorry if this question has been asked before but
I would like to know of a way to suppress error messages like:
'DBD::mysql::st execute failed: Duplicate entry.... at line 40'

I have tried the following:
    $res = $insert->execute() or die "Not Inserted\n";
and...
$dbh->{RaiseError} = 0;
but those do not work.

Thanks in advance.
-Gohaku