I have seen few people hitting an error when trying to register a COM server dll on windows 7. The error reads: "The module ""%1"" may not compatible with the version of Windows that you're running. Check if the module is compatible with an x86 (32-bit) or x64 (64-bit) version of regsvr32.exe." So what is going wrong.
There could be multiple causes to this problem.
If all these do not address your problem, then you may turn to your old friend, the debugger. Just launch regsvr32 in the debugger and check why did it fail when calling the LoadLibrary.
Hope this helps.