cycles viewport rendering

Hi.
I’m enjoying cycles interactive viewport rendering immensely. Or at least I was. Whenever I try to viewport render with cuda on a GTX560 I get an ‘Unknown Error’ message and this appears in the console:

CUDA error: Unknown error
CUDA error: Invalid context in cuMemAlloc(&device_pointer, mem.memory_size())
CUDA error: Invalid context in cuMemsetD8(cuda_device_ptr(mem.device_pointer), 0, mem.memory_size())
CUDA error: Invalid context in cuMemAlloc(&device_pointer, mem.memory_size())
CUDA error: Invalid context in cuMemcpyHtoD(cuda_device_ptr(mem.device_pointer), (void*)mem.data_pointer, mem.memory_size())
CUDA error: Invalid context in cuGraphicsGLRegisterBuffer(&pmem.cuPBOresource, pmem.cuPBO, CU_GRAPHICS_MAP_RESOURCE_FLAGS_NONE)

F12 and command-line rendering work fine with cuda, it’s just the viewport. The only thing I have changed recently is that my nvidia card no longer runs my X11 display (I’m on linux 64bit) but is now dedicated to cuda and my onboard cards runs the display. This is happening on 2.61 and 2.61.4 versions of Blender and I am running cuda-tookit 4.0, gcc 4.5.2 and nvidia-drivers 290.10.
Before I go back to the old set-up I just wondered if anyone here might know what’s going on.
Cheers
Ryan

hi have you find a solution for that?
I’ve the same problem with windows 7.