radeon 5970 wont mine

[nesic1]

i have problem with 5790, in guiminer it shows Mh, gpu usage is 99% but for some reason it display in console this error, also there is no accepted or invalid shares, number of shares is 0

"
2013-05-17 15:48:41: Listener for "3": pool.50btc.com:3333 17/05/2013 15:48:41, started OpenCL miner on platform 0, device 4 (Cypress)
2013-05-17 15:48:41: Listener for "3": pool.50btc.com:3333 17/05/2013 15:48:41, checking for stratum...
2013-05-17 15:48:42: Listener for "3": pool.50btc.com:3333 17/05/2013 15:48:42, no response to getwork, using as stratum
2013-05-17 15:48:52: Listener for "3": pool.50btc.com:3333 17/05/2013 15:48:52, Verification failed, check hardware! (0:4:Cypress, 6f32ef9e)

"

[ssateneth]

stop using poclbm. use bfgminer or cgminer

[nesic1]

on guiminer scrypt fort LTC it works ok but on guimine for BTC  it wont, i manage to solve this but i reinstall windows and now cant remember how i solve it, i use guiminer because i want 2nd core ti mine and first need for windows use

[Tywill]

Why not use cgminer?