Oh by the way busdriver72 - Welcome to the Windows 7 Forums website! We almost forgot out manners.
Yes, make sure the disc you're using for the "fixmbr" is the same bit version.
ALL retail full and retail upgrade packages of Windows 7 come with both the 32-bit and 64-bit install DVDs.
Only the OEM (system builder) version comes with a single disc, either 32-bit or 64-bit and less fancy packaging. (Plus the tech support is provided by the system builder, not Microsoft.)
Ultimate just offer a few more features/options over the Professional version.