Do you have something plugged into the line inputs in the back? The way the Firepod is wired is this:
Mic Pre & Instrumnet Pre
|
preamp output
|
preamp input normal contacts
----switching plug----
preamp input input contacts
|
ADC
Thus, if you have nothing plugged into the line input on the back, the front inputs are active. If you have something plugged into the line inputs, the front inputs are disconnected.
If you're wiring it up through a patchbay, you'll want to use a patchbay set to normalling mode so that the patchbay jacks connect the preamp output to the preamp return (line input).