That already got resolved in alpha build 478. Read this from http://www.shardstorm.com.
If you still have trouble, try loading sfx using WAV files with a bitrate of 22050 and either 8-bit or 16-bit. Try converting it to that bitrate, or re-create it and save it using that bitrate.* Attempting to loading a stereo SFX no longer crashes ZQuest upon playback. ( DarkDragon, 2007-07-14 01:45:07 )