You could try the following:
in ./global.php find:
PHP Code:
if ($servertoobusy AND !($permissions['adminpermissions'] & CANCONTROLPANEL) AND THIS_SCRIPT != 'login')
And replace by:
PHP Code:
if ($servertoobusy AND !($permissions['adminpermissions'] & CANCONTROLPANEL) AND THIS_SCRIPT != 'login' AND !($vbulletin->userinfo['usergroupid'] == 5 OR $vbulletin->userinfo['usergroupid'] == 7))
The above will only work for primairy usergroups.