I was having problems with this reg fix too. Three things that helped:
1) Make sure you have your phone set to announce incoming calls through the phone's speaker if you aren't using bluetooth. That was my first mistake. I had checked it once, but somehow during a reset it got set back to "Bluetooth Only."
2) For some strange reason my phone had an extra slash in the following key:
My Device\Application Data\Volatile\\TSCallerID.wav
I changed it to the following. Not sure if it helped or not (maybe it can recognize double "\"):
My Device\Application Data\Volatile\TSCallerID.wav
3) Make sure you in the Voice Command settings that you don't have it set to announce calls only during free times. Otherwise, if your phone has you scheduled for a meeting or event you won't hear the command come through.
Hope this helps.