How to make MVC4 web.api aplication referenced with ATL COM (dll) work on IIS 7

Question

I need my MVC4 web.api application to work with simple Com-object (ATL dll). All works fine on development server but when I publish the project to local IIS I've got error message

Unable to get the COM class factory for component with CLSID {E3D8B330-0622-4857-99D2-A72EB7A4CDE3} due to the following error: 80040154 Class not registered (Exception from HRESULT: 0x80040154 (REGDB_E_CLASSNOTREG)).

I'd used regsvr32 to register my dll. I even made sample console app that use same dll and all works fine in this way.

Any suggestions?

Answer 1

Can the test app run successfully using the credentials that IIS is running under?

If not, does the account IIS is running under have access to the registry key?

Is the app pool 32bit or 64bit; does it match the COM DLL?

Answer 2

Solved!

It is required to build COM-object (dll) for x64 (see Project's properties in VS). I have Win7 x64 installed so IIS runing on it is x64 too (I guess).