cuda video encoder not working with driver 340.52-whql

Hi NVidia supports and all
When I upgrade the graphic driver to 340.52-whql version, the NVidia CUDA video encoder do not work any more. The error message say that the nvcuenc.dll is missing. It seems that the drvier 340.52-whql version has remove the nvcuenc.dll. I come to notice that there is NVENC API for video encoding task. However the NVENC API is only working on Kepler-class GPU.
How can I run the video encoding task on the Fermi-class GPU ? Is there any way to go with CUDA video encoder? Will the futrue driver version fix this issue?

any advice will be appreciated

The NVCUVENC API is moving into an unsupported status. This is documented in the CUDA 6.5 CUDA toolkit:

http://docs.nvidia.com/cuda/cuda-toolkit-release-notes/index.html#unsupported-features

"CUDA Video Encoder (NVCUVENC) Building applications with the CUDA Video Encoder interface is no longer supported; however, the driver will continue to run applications built against this interface. We recommend using the NVIDIA Encoder API (NVENC), a newer video encoding interface that is available at https://developer.nvidia.com/nvidia-video-codec-sdk."

Yes, I understand this does not completely explain your case, as it indicates the driver support should still be there, but the point is that NVCUVENC is going away.

Probably the simplest solution might be to revert your driver to the previous version that you were using.