When using the Network Skins 2 mod I use the normal roads to establish the outside connections using the mentioned mod but when I try to make a new out side connection it gives me a NULL error.

For roads its fine. I make default highway road an outside connection and it gives me a null error but it still spawns cars. Though for trains I use the default tracks and it gives me a null error and not trains spawn.

I turn the mod off and reload the map and it still gives me null errors after the mod has been deactivated though the unlimited outside connection mod is still on.