The resultcode is not documented as a possible result of IMFCaptureSource::GetAvailableDeviceMediaType.
I can't give a sample without the whole code explained.
In the mean while this result is solved by implementing WaitForSingleObject(Event, INFINITE), before calling this method.
When IMFCaptureSource is created from IMFCaptureEngine::.GetSource the engine needs to sync because the IMFCaptureEngine methods are processed a-synchronous.
And that's the reason a HResult (0xC00D36B2) will be returned when IMFCaptureSource methods waits to be completed..
Now, it would be handy to add this resultcode and explanation here