I am getting the above message on one of my mining rigs, with a lot of disconnects to the mining pool as well (see below).
07/09/2011 06:43:58] Result: bc1528a8 accepted
[07/09/2011 06:44:17] Warning: work queue empty, miner is idle
[07/09/2011 06:44:36] Result: ca84b3a9 accepted
[07/09/2011 06:44:48] Result: 3286dee8 accepted
[07/09/2011 06:45:42] Warning: work queue empty, miner is idle
[07/09/2011 06:45:48] Disconnected from server
[07/09/2011 06:46:02] Connected to server
[07/09/2011 06:46:19] Result: 69a3eb6a accepted
[07/09/2011 06:46:24] Result: f304edb8 accepted
[07/09/2011 06:46:26] Result: 5a14529d accepted
[07/09/2011 06:46:30] Warning: work queue empty, miner is idle
[07/09/2011 06:46:35] Disconnected from server
[07/09/2011 06:46:55] Connected to server
I've read on other posts that this could be an availability issue with the pool's servers so I've tried both BTCGuild and BitClockers pool, with the same results. The strange thing is that I have another rig pointing at BTCGuild and it seems to be running just fine.