Can you send me the NMEA output from your receiver (using GPSD or direct rfcomm/cat)? This would help me determine the nature of your problem.
Maemo Mapper never sends any data to your receiver - it opens the bluetooth connection strictly for read-only access. What model of receiver do you have? Does it have a auto-power-save feature that would cause it to stop emitting NMEA data after 5 minutes of being disconnected?
The combination of the two of your problems might imply that the connection is getting dropped soon after it is established. The next time that Maemo Mapper seems to get stuck at "Establishing GPS fix", try disabling the GPS receiver (in the menu) and re-enabling it, and see what happens.
Did this change with v0.2? That is, did things work fine in v0.1?