If you have more than 1 AT card in your system, and you are using a high or mid-level development environment to write your code (Visual Basic, C++, etc.), you may notice unspecified errors popping up and crashing your application. Usually, this is occurs when you open Motion Architect first, and then attempt to run your app.
Motion Architect uses the SetNTParam function to initialize, assuming there is only one card in the system. Once this function is called, it starts the WinRT driver and subsequent attempts to initialize using the SetNTMultiCardAddress function will fail. The best solution is not to use Motion Architect if you are planning on using your own application. If you've already done the deed, you'll need to purge the Windows registry (discussed in a separate FAQ).