Got this on 0.33b2
Detecting OpenCL-capable GPUs...
CL_UNKNOWN_ERROR -1001
Specs: Radeon 7970, win7x64, driver 15.12.
Other miners(claymore,xmrig) run successfully on this pc.
GPU Miner didn't work on Windows 7. It requires Windows 8.1 and higher.
JCE, I think this requirement is need to be placed on 1st page and bolded!