"Active X component cannot create object" in Diadem 8.1 on a call to the VBS function CreateObject (used to create a file selection dialog). The same code works correctly on another system running the same Diadem version (but potentially with a different set of installation options).
This sounds like a problem between the ocx you are trying to link to in the CreateObject() command and your operating system. Is the ocx registered with the operating system on the computer this error occurs on?
Try creating a VBS file with only the CreateObject line of code in it. Then double-click on that file name in your Windows Explorer. That will launch the Windows VBScript host with the file you double-click. If that also gives you a similar error, then you need to work on registering that ocx with the operating system.
I'd also be happy to try this out myself if you'll send the ocx and that CreateObject line of code.