This means that all media devices in an MRGL were tried but unavailable. This could mean that a conference/transcoder resource was needed for a particular call, but all resources were in use. It could mean that music on hold was requested for a call, but the server was unavailable. Also, as the following post indicates, it can happen with a misdialed number. If you saw this alert a time or two and had no complaints, it's probably nothing to worry about. If you see this alert repeatedly and have complaints that conferences can't be initiated, etc., you may need to look at adding additional resources.

http://forums.cisco.com/eforum/servlet/NetProf?page=netprof&forum=Unified%20Communications%20and%20Video&topic=IP%20Telephony&CommCmd=MB%3Fcmd%3Dpass_through%26location%3Doutline%40%5E1%40%40.1ddcedee/0#selected_message

Hope this helps. If so, please rate the post.

Brandon