Kris FWIW:
I have been using the following technique for over 6 months (on 6 different volumes on 2 different machines), always with no problems.
In my emails with Alsoft, they remained steadfast that the genesis of the problem lies with QT.
1. Quit DiskWarrior 3.x
2. Control click on DiskWarrior 3.x and from the contextual menu select "Show Package Contents"
3. Locate the "Complete.aiff" sound file - the path is: - DiskWarrior 3.x app -> Contents -> Resources -> Complete.aiff
4. Rename the "Complete.aiff" sound file "Alert Complete.aiff" - then close ALL windows"
And joy again returned to Camelot.