Just in case anyone comes across the same issue, I managed to fix it by going into the 'C:\ProgramData\Running with rifles' folder(on Vista) and editing the line in config.xml to say:
<audiodevice value="1" />
For some reason it kept going back to 0 every time I applied changes to the settings. Also don't make the same mistake I did and look for Program Files
instead of ProgramData
This might work reverse for some, or not at all, I dunno. I didn't write the code after all! This is just how I fixed it.
(Perhaps it'd be neat to have a setting that allows you to pick an audio device if another doesn't work?)