the username has special characters in it
This is fixed for v2.5.7+
you should do the following to quick-fix it:
open /arcade.php
search for
Code:
$DB->query("INSERT INTO ibf_pmtext (fromuserid, fromusername, title, message, touserarray, iconid, dateline, showsignature, allowsmilie) VALUES ('".$senderid."', '".$sendername."', '".$title."', '" . addslashes($message) . "', '" . $recipient . "', 0, " . TIMENOW . ", 0, 0)");
and replace it with
Code:
$DB->query("INSERT INTO ibf_pmtext (fromuserid, fromusername, title, message, touserarray, iconid, dateline, showsignature, allowsmilie) VALUES ('".$senderid."', '".addslashes($sendername)."', '".$title."', '" . addslashes($message) . "', '" . $recipient . "', 0, " . TIMENOW . ", 0, 0)");