First off, this should be moved to the general message board. You may get more responses there. This is the general interview board. No worries, it is a common misconception.
I am not specifically familiar with that GPS but you might want to try a couple of things. Check your documentation and see if you can update the "Almanac". The almanac is a database of the satellite ephemeris data. This is the orbital data for the satellite constellation. If this data is out of date the unit will be looking for all the wrong sattelites and will have to acquire a signal, receive the information, and figure out a rough approximation of it's location. Updating the almanac usually entails leaving the unit with a WIDE view of the open sky for an extended period of time. Almanacs will go stale if the unit has either not been utilized for some time or has had a great displacement in distance since it has last been turned on/off. The unit will always usually assume that it is being turned on at the last location is was at when turned off.
The other thing is to see if you can insert what some manufacturers refer to as a "seed" position. This is an approximation of where you are currently located lat/long wise. It does not have to be too accurate, just any lat/long of the nearest large city or know location will do.
Try these things, otherwise just make sure that the unit has a good unobstructed view of the sky for a good while.
Note: I have seen problems with some units not getting real good signals in proximity to large metal buildings, like hangers. That could just be the GPS unit, or it might be some kind of signal attenuation. GPS signals are very weak so they might be adversely affected. This is just my conjecture as I am no expert when it comes to this kind of stuff.
