Cannot "Enter Time Machine" from Mountain Lion Upgraded to Mountain Lion yesterday. Time Machine backups continue to run without any reported errors. (Backups are to a HD shared by a Lion Server on the network).

Problem is When I choose Enter Time Machine (or double-click on the Time Machine application icon) nothing happens. No window. No error. No...nothing. I do notice that the remote HD mounts in the Finder... but that's it. 

I've reviewed a similar question which appears to be Lion (or perhaps Snow Leopard) related. But this is not acceptable as I don't want to erase my whole backup and start anew...as I can't afford to toss my only Lion backup.

Anyone know what's up? And how to get my TM working properly under MLion?
I had to reformat the external drive I use for Time Machine. It said there was a permissions problem, that it was Read Only - which it wasn't, and a look at the Info for it confirmed it was Read &amp; Write. Still, I just erased the drive and started again. Works fine now.