If your using IG3 or IG4 the command to use is "AP03"
If your using IG2 the command to use is "GPS1"
If your using Mapmonkey the command is "MMGPS"
If your using Freedrive the command is "FREEDRIVE"
what menu do you see when you click the OPT button? If you see anything that does not this following list, then you have an old version of the skin.
If you dont see this list, update the skin to the latest version.