It looks like you are getting an Exception.Assertion and the application has crashed. If you work for Blizzard Entertainment and have access to the C++ source code for the program Warcraft III.exe, then you should recompile the program with debug symbols included. For example, on the g++ gnu C or C++ compiler you can use the -g argument to recompile the application with debug symbols. Assuming that Warcraft III.exe is compiled with MSVC.exe, I would imagine a quick internet search could help you find how to enable debug symbols on MSVC, although I forget the name of the setting off the top of my head.
So, if you recompile the Warcraft III.exe again but with debug symbols enabled, you can probably reproduce this crash and then decipher a more meaningful stack trace regarding the cause of the problem. You might also be able to use the source code for the program Warcraft III.exe to match against the binary.
However, if you do not work at Blizzard Entertainment, then you do not have access to that code so you can use the Guess And Check strategy, where you Guess and then you Check if you were right about the problem.
Edit:
To help you with the Guess And Check, I suggest that you Save Replay of the game and then watch the replay. Sometimes this will help you Guess about the problem, if you see the replay at the moment of the crash.
