Sounds like a DMS issue. You may as well check the cable connections, and try resetting your Kenwood head unit.
Assuming neither of those things work, put your DMS in the cartridge and check both partitions for errors. A disk defrag also won't hurt. Once your disk is error-free and defragmented, load up PMM and go to options. There is a button I think under DMS maintainence to "Fix DMS database." Run that, save and eject and then try the DMS in the car again. That should do it.