First Maemo Mapper works very nicely on the N810.

Somehow your gps settings got changed. It looks like you checked GPSD host. That is bad with N810.

Open Maemo Mapper -click on menu - settings - GPS
make sure bluetooth is checked. check ok.
click on menu again - GPS - Enable GPS should be checked.
click anywhere off the menu to close it.

I hope I explained this clearly and it helped.