If the panel was made for FS2002, the GPS will not display. This can be avoided by editing the panel.cfg file. Replace the old GPS window with this one:
[WindowX]
Background_color=16,16,16
size_mm=148,97
window_size_ratio=1.000
position=0
visible=0
ident=GPS_PANEL
window_size= 0.265, 0.277
window_pos= 0.653, 0.723
gauge00=fs9gps!gps_500, 0,0,148,97
Replace the X with the old window number.