Left click on view at the top of GUIMiner and then show console. Stop and restart both your miners. What is said in the console?
2013-03-20 12:04:27: Running command: poclbm.exe c0ikws.joe:
[email protected]:8332 --device=1 --platform=0 --verbose -r1 -v 2 -w 128
2013-03-20 12:04:27: Listener for "5770" started
2013-03-20 12:04:28: Listener for "5770": 20/03/2013 12:04:28, need more than 1 value to unpack
2013-03-20 12:04:29: Running command: poclbm.exe c0ikws.JoePc:
[email protected]:8332 --device=0 --platform=0 --verbose -r1 -v 1 -w 256
2013-03-20 12:04:29: Listener for "Card" started
2013-03-20 12:04:29: Listener for "Card": 20/03/2013 12:04:29, need more than 1 value to unpack
2013-03-20 12:04:29: Listener for "5770": api2.bitcoin.cz:8332 20/03/2013 12:04:29, started OpenCL miner on platform 0, device 1 (Juniper)
2013-03-20 12:04:29: Listener for "5770": api2.bitcoin.cz:8332 20/03/2013 12:04:29, checking for stratum...
2013-03-20 12:04:30: Listener for "5770": api2.bitcoin.cz:8332 20/03/2013 12:04:30, diverted to stratum on stratum.bitcoin.cz:3333
2013-03-20 12:04:30: Listener for "Card": api2.bitcoin.cz:8332 20/03/2013 12:04:30, checking for stratum...
2013-03-20 12:04:31: Listener for "Card": api2.bitcoin.cz:8332 20/03/2013 12:04:31, started OpenCL miner on platform 0, device 0 (Tahiti)
2013-03-20 12:04:31: Listener for "Card": api2.bitcoin.cz:8332 20/03/2013 12:04:31, diverted to stratum on stratum.bitcoin.cz:3333
2013-03-20 12:06:26: Listener for "5770": api2.bitcoin.cz:8332 20/03/2013 12:06:26, checking for stratum...
2013-03-20 12:06:27: Listener for "5770": api2.bitcoin.cz:8332 20/03/2013 12:06:27, diverted to stratum on stratum.bitcoin.cz:3333
2013-03-20 12:06:30: Listener for "5770": api2.bitcoin.cz:8332 20/03/2013 12:06:30, Verification failed, check hardware! (0:1:Juniper, 76c88b29)
2013-03-20 12:06:37: Listener for "5770": api2.bitcoin.cz:8332 20/03/2013 12:06:37, Verification failed, check hardware! (0:1:Juniper, 76650588)
2013-03-20 12:07:01: Listener for "5770": api2.bitcoin.cz:8332 20/03/2013 12:07:01, Verification failed, check hardware! (0:1:Juniper, 7b843793)
2013-03-20 12:07:19: Listener for "5770": api2.bitcoin.cz:8332 20/03/2013 12:07:19, Verification failed, check hardware! (0:1:Juniper, f42fd40b)
2013-03-20 12:07:34: Listener for "5770": api2.bitcoin.cz:8332 20/03/2013 12:07:34, Verification failed, check hardware! (0:1:Juniper, 1ce8ebd9)
2013-03-20 12:07:46: Listener for "5770": api2.bitcoin.cz:8332 20/03/2013 12:07:46, Verification failed, check hardware! (0:1:Juniper, 54756c90)
I tryed lowering de clock rate of the card with no result.
I have latest drivers.