I've just started with Bitcoins, I have a Radeon 6870 so I thought I could get some work in before everything moves to the new ASCI's.  I've started with GUIMiner, I've tried cgminer but it gives me awful hash rates (150k vs 275M-300M).  I've tried bitminter too, but I'm getting faster rates with GUIMiner.

Anyways, my GUIMiner keeps having errors.  I can get it running and everything, but after it finishes a block it fails to start a new one, and I have to "stop mining" and "start mining" again.  This happenes every 5-10 min (though, it's been plugging along for the past 20 min or so now.... It's only a matter of time.)  I've been searching and searching online, and I've found people with the same problem, but no solutions.

Here is the console window: (the important bits)

Listener for "MinerJoe" started
Listener for "MinerJoe": 21/04/2013 15:27:36, ADL_Adapter_ID_Get failed, cutoff temperature disabled for 0:0:Barts
Listener for "MinerJoe": 21/04/2013 15:27:37, started OpenCL miner on platform 0, device 0 (Barts)
Listener for "MinerJoe": btcguild.com:8332 21/04/2013 15:27:37, checking for stratum...
Listener for "MinerJoe": btcguild.com:8332 21/04/2013 15:27:37, using JSON-RPC (no stratum header)

It's happy here, it runs for awhile, then: (the time gap here is only ~1 min, but usually it lasts longer)

Listener for "MinerJoe": btcguild.com:8332 21/04/2013 15:28:21, warning: job finished, 0:0:Barts is idle
Listener for "MinerJoe": btcguild.com:8332 21/04/2013 15:28:38, warning: job finished, 0:0:Barts is idle
Listener for "MinerJoe": btcguild.com:8332 21/04/2013 15:28:42, IO errors - 1, tolerance 2
Listener for "MinerJoe": btcguild.com:8332 21/04/2013 15:28:42, long poll IO error

And I get long poll error over and over again until I restart.  Some other things that come up with the long poll error are:
 Listener for "MinerJoe": File "GetworkSource.pyo", line 198, in long_poll_thread
 Listener for "MinerJoe": File "GetworkSource.pyo", line 106, in request
 Listener for "MinerJoe": File "GetworkSource.pyo", line 144, in timeout_response
 Listener for "MinerJoe": File "httplib.pyo", line 1018, in getresponse
 Listener for "MinerJoe": ResponseNotReady

Any ideas?  I'll donate to whoever helps me fix it...