x86 with COM Interop Compiled on x64

I have a small application that I wrote that imports both the iTunes and MediaMonkey COM interfaces. The app is developed and built on my laptop with is x64 but 开发者_高级运维run on my media PC which is x86. It runs perfectly fine on the x64 machine, but when I try to run it on the x86 media PC it fails to load. If I disable the MediaMonkey part it works fine with iTunes, but I cannot get it to work with the MediaMonkey COM enabled.

The application is compiled for .NET framework 4.0 and as x86 specifically.

Any ideas what I might be doing wrong?

Following the lengthy comments conversation, here's my suggestion as a real answer:

Try to reinstall MM on you media PC, using "run as administrator" for the installation. There's a somewhat dated discussion in MM forums - Installer doesn't install COM Object properly. If the MM COM server was not registered properly, it will not be available.

Also, I don't know if this is relevant for this case, but FWIW - there might not be a DLL to register. ActiveX EXEs can use the default marshaller, without a need for a proxy-stub, and can be registered directly.