Not a problem, I should have included instructions right from the start. Right-click on the PlaneShift
desktop icon, hit Properties, and type
-relight at the very end of the Target line, like so:
Before you do this, make sure you are logged off in the map that has these lighting problems. When you run PlaneShift afterwards, the loading time will be far longer. If the problem is fixed, take out -relight from the shortcut so that you don't repeat this every time PS runs.