I came across this issue when I tried to access the console view for a VM running on my XP box. For the most part this VM runs without problem, until recently when I found the VM was running OK, but VMware workstation 6 was reporting it as Powered Off and it came up with an error "cannot find a valid peer process to connect to".
This isn't immediately a problem as my VM runs my Exchange and SharePoint web server which still chugged away happily in the background (as evidenced by the processes still running in Task Manager, and my being able to access it through the web and RDP). I also have it setup for RDP access, so I can get to it from any PC or Laptop around the house, should I need it.
The problems start to occur when you use the PC it is hosted on as your main PC, and you need the console to access the VM from an admin point of view such as snapshots, restarting, and cloning etc...
So after some digging I managed to find the answer, and typically with any problem of this kind in windows, a service had failed to start (probably due to permissions on the local machine). The service in mind was the 'VMware Authorization Service' which I restarted and KAPOW!!!! The VM was accessible from the console again.
I have not officially tracked down why the service failed to start, but I have set the service actions to restart the service if it fails, and then on the third failed attempt, set a batch file to run along the lines of...
REM The VMware Authorization Service failed to restart...
Pause
This should run the batch file if the service fails and leave the message on the screen so I can remedy the next time I look at the desktop. Crude solution but at least I'll know when it has failed and hopefully track down the cause.