On a Concord 4 there are limited local control options for Z-wave, however you can still add devices. If you are having trouble getting the system into pairing mode or acknowledgement remotely, try pairing the device locally.
Instructions for local installation of Z-wave devices can be found here. Any luck?
If your Z-wave radio is having general trouble, try a power cycle of the system. Unplug the transformer, then unplug the battery. Wait 2 minutes, then power back up battery first. About 5 minutes after booting up try putting the radio into learn mode again in Alarm.com.