Hmmm this is a new one to me. I would start by checking:
- The volume level in iG, even though you are getting audio outside of RR, its
just a thought.
- Go into the Mixer inside RR and check the "Wav" volume, and make sure it is not muted.
- Check that iG itself is not muted
I know these are pretty basic things, but I can think of no other reason that audio from MP3's in RR is working, and not iG.