Oh wow! I was going crazy trying to figure out this problem and I just found this thread and it worked for me too!!!
I'm so glad this thread was here.
I'm also irritated at Nvidia though because their latest approved driver is even worse, it crashes my entire system...
only the beta version 285.79 let me export video without any crashes. I haven't tried the other betas to see where the bug gets introduced...but not sure if its worth experimenting now that its working for me.
just scary that their official versions have such horrible bugs