Have you tried another app incase it is Mapopolis that is at fault. There is a free app on the home page of PPF you might want to try?
http://www.pocketpcaddict.com/forums...ools-free.html If that doesn't work I can only suggest your unit has failed for what ever reason. If you have a steady hand as a last ditch test you might want to retouch all the solder points in the unit, might be a dry joint, particularly between the aerial and the circuit board giving a bad signal. Lucky for you though BT GPS have dropped a lot in price so a replacement would be very cheap now.