Hi Dwayne,
I too am experiencing this error. It seems to come from when "Marker" entities are added (lights, player starts, triggers, etc.).
I'm not exactly sure what is causing it, but I would make progressive saves of your levels, and add markers with incremental saves. If the problem re-surfaces, add the last "good" map, with the latest map that has the problems to a zip file, upload them so someone can look at them (FPSC crew). this way they can figure out what is causing the issue and (hopefully) make a patch to resolve it.
Keep on working though - and good luck!!
-Phantom
Faith is daring the soul to believe what the eyes cannot see...
