Problem with Ajax'd Mail()

[totalstranger]

I'm hoping someone can help figure out how to stop a message that
appears to be generated by my web host when sending to an non-resolvable
email address that is supported by my web host. Things work correctly
when sending to an invalid e-mail address off my web host .

The message returned is
+:/home/xxxxxx/dead.letter...s aved message in /home/xxxxxxx/dead.letter
and it ends up before the data in my return statement which then fails
when my AJAXed javascript chokes attempting to EVAL the result.

I've tried everything I know to capture, discard or suppress the mesaage
including using
Ob_start() before the mail command
with an Ob_end_clean() prior to the return statement.

Here's what currently is coded that also does not work
# kill error display if mail fails
ini_set ( "display_errors ", "0" ); #Also tried FALSE
ini_set ( "error_reportin g", 0);
if (!@mail($visito rmail, $subject, $notes, $hdrs))
{
return "document.getEl ementById('resu lt_msg').innerH TML= \"Sendmail
has failed.\";
";
}

I admit so being something of a PHP neophyte and any help with this
issue would be appreciated.

Thank you