Try turning off BASS_SAMPLE_FLOAT in mAirListConfig (either WDM/DirectSound config or ASIO config, depending on the method you use).
I don’t know much about that particular model, but generally, Digigram cards are known to have very poor “standard audio” (WDM, ASIO) support. They work very well with applications specifically designed for them (that is, using their private driver model), but not so good with normal audio applications.