Try reading this post (http://www.feral-heart.com/index.php?option=com_jfusion&Itemid=2&jfile=index.php&topic=10423.msg144795#msg144795) to see if any of this might help.
Also, sometimes custom maps get caught in a server hiccup and won't connect, which in turn would have to wait for a server reboot(which happen time to time) to be refreshed. Hopefully this isn't the case.
~ Whisper