We've noticed that there was a bug in the AIT CODEC around ColorContexts. When trying to view AIT files through WPF APIs, this bug will maifest itself as not being able to open the image, though WICExplorer was able to display it.
The fix is relatively simple for now... just commenting out the support for ColorContexts. In the next release we do, there will be a full fix here.
AIT CODEC Code (February CTP): AITCodec_code.zip
AIT CODEC Compiled (February CTP): AITCodec_compiled.zip