The bug with Ambient crashing after doubleclick on empty file seem to be not directly related to the new classes, but new classes could trigger it. The real bug is hidden in wave.demuxer. When its format recognition routine tries to feed the first 4 bytes of file, it falls into an endless loop, when the file is shorter than 4 bytes.

Try to check if your problem is related. Delete (or move somewhere) wave.demuxer from MOSSYS:Classes/Multimedia, reboot and try to retrigger the bug. You can also run MediaLogger in the background and try to capture its latest error messages.