Ensure that the FireWire card is being detected by the ADA-8/ADA-8XR hardware by using the "Interrogate Modules" option in the ADA-8/ADA-8XR's menu.
Next, ensure that the Source and Destination of both paths is set to the relevant slot which houses the FireWire card. If in doubt, re-load the factory FireWire store.
Finally, check that your operating system is suitable and that your FireWire ports are functioning correctly. Windows users may have to re-install the FireWire drivers when adding a new FireWire card.
If you still have problems, please contact tech.support@prismsound.com.