Yes, it does work in Windows 7 64-bit (it's what I used to use). It will run the code in 32-bit mode.

As for the error message, it's a bit hard to understand what went wrong from such a brief description. Does omc.exe work fine for example? Or is this a problem with firewalls?

Have a look in the task manager and see if there is a hanged omc.exe there. If it is then just kill it.
Then try to restart OMShell again.

Also make sure omc.exe, OMShell.exe, OMNotebook.exe and ext.exe are added to your firewall
exceptions as they need local network communication.

If this doesn't work post back and I can give you more detailed instructions on how you can
start omc.exe manually before starting OMShell.

Cheers,
Adrian Pop/