COM Interop Catastrophoic Failure in IIS

[Feroz]

I'm trying to invoke a method on a 3rd party COM(using the interop)
inside my web service and it throws the following error: "Catastrophic
failure (Exception from HRESULT: 0x8000FFFF (E_UNEXPECTED))"

I get this error only when I host the webservice on IIS. If I host it
on Visual Studio Development Server, it works fine. It works fine in
other windows applications too.

I'm using Windows 7 64-Bit.

Thanks in advance for any answers.