the lightmap on a large displacement i have keeps setting itself to 130. i change it and close the box, when i re-open the box it's back to 130 again. i know it has to be a multiple of 2 for the game to run so my map is currently in the Doldrums 'till i can fix it.
I assume it's a VERY big displacement then? If a displacements become too big for the entered lightmap value, it will jump to the smallest value that works what that size. To jump to 130 it would have to be very big though. Try cutting in half twice (well in 4 actually), and see if you can make it lower then. Don't forget to take a backup.