Ah ok... so the sounds import a-ok, just when you add them to a soundgroup?
Make sure that you're not trying to add the sound-group into the sound-group.. I've done that sorta thing with Material/Textures a few times.. usually results in a SDK crash as it goes into infinate loop land.
Aside from that, I've never seen an issue like this speciifc to sound.. the sounds play OK and everything?
Hmm, maybe I do it a little bit wrong. My steps are as follows:
1. load the .uax
2. create new soundgroup
3. (try to) import a new sound into soundgroup
4. assign properties to the sound (such as Distant=True etc.)
Another strange problem is this:
I rename the original DH_WeaponSounds.uax to DH_WeaponSounds.bak and move it to another folder. I open the SDK and go to the sounds menu. And what I see? All my created groups and sounds are gone! I have to manually load my new DH_WeaponSounds.uax into the editor to have the groups and sounds back. The editor loads the default automatically.