I added the following change to class.pop3.php on line 220:
//Check for possible auto-reply to ticket notification
if (eregi("(out.of.{1,5}office|auto.reply|out.until)",$var)) {
// delete the offending email (comment next line out if you don't want to autodelete)
imap_delete($this->mbox,$mid);
return null;
}