With the Bar done, dead and over, I decided to reinstall VMWare fusion... and quickly ran into a problem. VMWare kept saying it couldn't authenticate my Boot Camp installation, and suggested that my permissions were incorrectly set.
A quick knowledge base search led to the solution:
The fix is to re-create the Boot Camp virtual machine. To do this, delete the folder "~/Library/Application Support/VMware Fusion/Virtual Machines" where the tilde represents your home folder. Then restart Fusion and try your Boot Camp partition again.
If the problem persists, could you upload the file "vmware.log" that you'll find in the ~/Library/...blah... folder?
It's possible but pretty unlikely that you have an actual problem with your hard disk. Running a disk scan from within Boot Camp Vista could tell you.