Pointer - VMWare Workstation 6.5.x still has problems running on NT 6.0 and 6.1 x64 platforms (Vista and Win7, respectively). Even their techies aren't sure what it's all about, but crash analysis suggests something about faulty communication between real and virtual kernels.
( Aggravating circumstance is that problem manifests itself in different ways - for instance, your ability to run (or resume) a different (x86) OS in VMWare, whereas even that isn't possible. )
Possible workaround - install and run WMVare in WinXP compatibility mode, always with "Run as admin" command.
Note -- worked for booting x86 and x64 Debian kernel in VMWare after several VMWare crashes and reinstalls (and it still works, although it's a 'n00bish' solution)