Problem fixed
It occurs when message encryption or obfuscating is _not_ used.
The fix is quite simple:
In uddeim.php in approx. line 1240 you will find following code
Code:
$sql="INSERT INTO #__uddeim (fromid, toid, message, datum, totrashoutbox, totrashdateoutbox) VALUES (".(int)$savetoid.", ".(int)$savefromid.", '". $savemessage ."', ".$savedatum.", 1,".$savedatum.")";
change "$savemessage" to "$savemessage2".
That's all.