Just now I answered a problem like this in other thread, so I'll just copy what I said:
"Do you have your game nested in a lot of folders? Then move the game's folder as close to the local drive's root directory as possible. Having the game nested in too many folders frequently leads to an error in this site's games, where the game looks for a file with such a long path that such path is cut short at a certain amount of characters, thus making it impossible to actually find the file."
If you watch closely, the main error is that the game can't find one of Vili's skills, particularly a long-named one.