This is surely nothing that has anything to do with any of our products. The only FSDT product that uses sound in some way it's GSX, but it doesn't interact with the FSX sound engine, because it uses its own sound engine, based on OpenAL. And, GSX does't do anything while you are flying.
Does the crash happens with another airplane ? Maybe one of the sound files used by that airplane has a problem, like being in the wrong format, or corrupted, or missing, etc.