I was working on a map and it was almost finished until i managed to mess around a little bit... After messing around actually i saved the map as a different name in case it won't work again for some reason... and what happens now is: If i load the old or the new map files the map works fine but if i run the in game editor it crashes with the "UT3.exe has encountered a problem and needs to clos" or something similar to that... a few minutes before that i could check the map with the in game editor but now i can't do it anymore.

It's not the first time though... in the past i just restarted my PC and after that it worked fine... now i tried to restart and look for a solution but find none.

Any input please?