Well, you never know, this might just be the very cause for your issues
Windows on a Mac........ 
Had Bootcamp and one of the commercial emulators on my Mac to try and run some non-ported Windows programs, but they all suffered issues caused by this 'solution'. Uninstalled them all, and have a dedicated windows7 machine for specific use.
keep us updated.
`cheers,
Marius
I just formatted a partition with Disk Utility on Mountain Lion using the GUID table option, not the MBR option, no joy.
Formatted as NTFS file under Windows 7 w/o the DOS start up record, no joy.
I think I'll buy a Passport that I know will work and use this one as backup for my MBR.
Thanks to everyone who has been trying to help me.