[Asterisk-Users] IVR sounds not on certain inbound route

[MC]

Got 1 issue I can't seem to knock out of this particular box.

The IVR works fine on the zap channels and the incoming SIP routes. But 
coming in via the IAX2 route leaves me with a silent phone.

The prompts all work still letting me navigate the menu. But just can't 
hear anything.

This is with  A at H 2.8 (Asterisk 1.2.7.1, with FreePBX 2.1.0 also installed)

Any thoughts on where to start looking to solve this? Console shows it 
all executing fine.