Which build are you using, looks like an older one. Have you tried a file verify?
I am finding that if you are working on a large level and you test game it a few times, game guru does some strange things. Try restarting game guru and then open the map, save as a new name and see if that will clear it up for you.
If not then could you email me the map file to the below email address.
Intel(R) Core(TM)2 Quad CPU Q6600 @ 2.40GHz, 2400 Mhz, 4 Core(s), 4 Logical Processor(s), 8gb RAM, Nvidia gtx660, Windows 7 Pro 64bit