Limit on numbers of aircraft & scenery in FS2002

I have a large number of aicraft kept in a file separate from FS2002.The number installed in to FS2002 is about 200.Now when I install a new aircraft, it is seen to appear in the aircraft folder initially.The next time I fire up FS2002, the aircraft has been deleted.I know there is a limit to the number of sceneries to add to FS2002, as they do not appear on the scenery list. I currently have 208 separate sceneries. When I tried to install VFR Photographic Scenery, it appears in the sound.cfg file, but not on the menu.Does anyone know these limits?Thanks a lot.Vrystaat Dell 4100 P3, 120G HD,512 RAM,Geoforce 3.