Your comment clarified the statement on their site, regarding CUDA, which I found to be ambiguous at first.
NVIDIA doesn't support the CUDA H.264 encoder from the GeForce 340.43 beta driver
I incorrectly interpreted the 'from' as only those drivers, and not also future drivers.
So after reading Your above quoted comment, I re-read the instructions more carefully.
At first I assumed 32 bit .dlls went in in Win32, and 64 bit .dlls went in WOW64 folders.
And since it was not that important at the time, I gave up too easily.
Until later they were more important, for recording more GPU intensive games.
I include all these details in the Hopes it will help others, save time and difficulties.