Rahul, can you please send us the specs of your machine when you see the error (more details the better):
CPU, cache size, clock rates
GPU, brand, engine and memory clock rates
PCIe express lanes, Gen1 or 2
How often do you see the error?
Please send the info to ATTN: Newton, Udeepta at email@example.com
There is a bug in the parameters for calCtxIsEventDone() in the copy function. The context and event handles are switched. The call returns an error code that you may check. I think this should solve the issue.