Exactly the same thing happening with my late 2011 MBP 17" after going from Lion to Mountain Lion.
At least I learn't here not to bother trying to re-install.
Can you contact Apple and troubleshoot it, and let us know the results here? I wanted to contact Apple but my 2009 March iMac is out of Apple Care and Apple would charge me for support. So if you could turn this issue into Apple and see what they have to say about it. We would appreciate it greatly.
Thanks.