Just experienced a wasted 60 minutes trying to figure out why a C# project I've created (which is registered for COM Interop / CCW) couldn't be created from my test harness .vbs file (via CreateObject).
Background: I installed Visual C# 2010 Express on a 64bit Windows 7 platform, created my demo C# 'COM project', told VS to 'Register for COM Interop' - it all built without fail. However when I try and call into the COM object via a test.vbs file COM was complaining!
After some investigation (the /regfile switch on regasm.exe helped me out) I noticed that VS was using the 32bit version of regasm.exe which was subsequently writing the registry entries under the 'virtualised' WOW64 hierarchy (i.e. HKEY_LOCAL_MACHINE\Software\Wow6432Node) . Thus when I execute my .vbs (which internally uses the 64bit cscript.exe) then it couldn't find the COM object as registered (as it was only registered for the 32bit world).
Solution is to manually run the 64bit regasm.exe so the registry entries are put into the normal (and correct) place. Then your COM object will be visible to the 64bit world!
See here:-
http://support.microsoft.com/kb/956933
