i am getting the exact same error, and when i googled dump_wmimmc.sys, this was the first site it gave me =)
i seem to be getting this error a lot when i'm playing games, especially when i alt-tab out of games or when i'm exiting a game.
in my system events, i found this:

Driver detected an internal error in its data structures for .

For more information, see Help and Support Center at http://go.microsoft.com/fwlink/events.asp.

not very helpful...
i installed some newer drivers, version 84.21, for my 7800 GTX, but i'm still getting this BSOD.
any help will be appreciated =)