Nobody mentions that sound effects need to be mono?
If the sound is stereo it will only play over 1 of the channels. Only music is stereo.
Also the ogg format is not really necessary, it might be easier to change the extension in the .sounddata file to mp3 or wav, but if you are converting to mono, you may as well convert to ogg at the same time.
EDIT: also dont forget to put your sounds in a mod folder or the next update you will lose all your work.