Looks like other users have reported this problem back in January but no response.
I receive the error: "Host not found" on some phones as soon as I select the service from the phone. on Other phones I can see the 4 options joing meeting etc but when I select one of these I get the error again "Host not found"
I was wondering if anyboy had solution to this. CUCM 6.x can resolve the MPE Server either by host name or IP.