Well the 8700 doesn't have GPS so I have no idea what you mean.
For GPS to work, you need to be outside, with a clear view of the sky for it to find and lock onto the satellites. You also need a BB dataplan for the maps to work.
When you open BBMaps or GoogleMaps, try to locate yourself as close as possible to your true location on the map. For the first time, it will take several minutes to lock on as it has to download all the sat data and orbit tables. Make sure you go into the map application's menus and start the gps as well.