Just a random thought, but you are using a project file? (.dbpro)?
I know the executable would run from the temp folder if you are just loading the source from the .dba file, that would mess up any local paths used.
>edit<
Ignore that, we've already tried using absolute paths so it's not that.
Just to be on the safe side, check that the sound file is where DBP expects it to be with the
file exist() command; and if that comes back as 1 (Yes, the file exists), then I agree with Kezzla that its a DBP installation problem and will probably be fixed with a reinstall.