This debug error is showed at pop-up, insted messages and contacts:

ORA-00911: invalid character

SELECT u.id, u.firstname, u.lastname, u.picture, u.imagealt, u.lastaccess, count(m.id) as messagecount FROM m_message_contacts mc JOIN m_user u ON u.id = mc.contactid LEFT OUTER JOIN m_message m ON m.useridfrom = mc.contactid AND m.useridto = 3 WHERE mc.userid = 3 AND mc.blocked = 0 GROUP BY u.id, u.firstname, u.lastname, u.picture, u.imagealt, u.lastaccess ORDER BY u.firstname ASC;

    * line 686 of lib/dmllib.php: call to debugging()
    * line 54 of message/lib.php: call to get_recordset_sql()
    * line 87 of message/index.php: call to message_print_contacts()

ORA-00911: invalid character

SELECT u.id, u.firstname, u.lastname, u.picture, u.imagealt, u.lastaccess, count(m.id) as messagecount FROM m_message m JOIN m_user u ON u.id = m.useridfrom LEFT OUTER JOIN m_message_contacts mc ON mc.contactid = m.useridfrom AND mc.userid = m.useridto WHERE mc.id IS NULL AND m.useridto = 3 GROUP BY u.id, u.firstname, u.lastname, u.picture, u.imagealt, u.lastaccess ORDER BY u.firstname ASC;

    * line 686 of lib/dmllib.php: call to debugging()
    * line 84 of message/lib.php: call to get_recordset_sql()
    * line 87 of message/index.php: call to message_print_contacts()