When regsvr32 fails it gives you the error code.
Check the VC help to match this number to a error description.

The most common one is 485, which means that there is a dll missing. If this is the case, ensure that any dlls you are using are on the new system. Ensure that any MFC / MSVCRT dlls necessary are on the system, and that they are the same (or newer) version to the ones on the development system. And finally check that the oleaut32.dll & olepro32.dll (in windows system) are the same (or newer) versions to the ones on the development system.
If none of these work, try going through the list of dlls loaded when you run your program (shown in the debug window of VC) and check each of these.

But then again, the error code mighn't be 485 :-)