There seems to be a bug with the save and load dialogs. If you start Simutrans in a nightly revision, and click to load a game, the game will crash, without any error message. The same thing occurs if you try to save a game.
This applies to both gdi and sdl versions? I did not found anything suspicious under linux.
I have Windows GDI version of r6890 and there are no problems as said Dwachs.
Very strange. I just tried the stable version and had the same problem, and I know it was working before. Something changed to my setup; I don't know what. Deleting _cached.xml from my save folder seems to fix the problem. Perhaps that file got corrupted or something.