What version of the game are you running? I'm not entirely sure, but I think i see the problem. I just checked the crash log you posted and one of the things written in it is this:
"Message: Could not find file 'C:\Downloads\Pokemon\maps\poke\azalea.poke'."
Seems like the game is trying to load a script (or something, looks like the .poke files contains info on what kinda Pokemon can be found in the different game locations) and it crashes because it can't find this file. Maybe what happened was a wild pokemon battle was triggered in the cave, but the file containing the Pokemon you could meet could not be found? I don't have time to test this myself, but I just checked my own Pokemon folder to see if I had a file called "azalea.poke" in the poke subfolder, and heck, I don't. I'd imagine my game would crash aswell if i tried to do whatever it was you did.
For reference, I'm on 0.26.1