Aw, sadly none of those suggestions worked. I redownloaded 0.1 though and the sound worked on that version again. Certainly a bit interesting. On an unrelated note, I've noticed going into windowed mode tends to make the game a bit more crash-happy. Dunno if you've fixed that in the newer versions though.
(Also I'm using Windows Vista Home Premium, 64-bit.)
Sad indeed. There hasn't been significant changes that would affect the audio side since 0.1, other than where config.xml is located and how the dll's are installed.
Curiously, it does seem that beta 0.4 on your system can locate OpenAL dll's just fine, otherwise it would abort the game launch early I'm pretty sure.
If the config.xml doesn't have a field for audiodevice or it is zero, it is possible that the audio is just skipped -- again, it appears that the config.xml is correctly located on your system as you can switch between windowed / fullscreen mode, and you already checked that the audiodevice is indeed 1.
I can perhaps give you an experimental build of the game to try out, I'll add some traces in the log to see how far the audio playback goes or if it fails somewhere unexpectedly. Let me know if you want to try it out.