I as well am having the same problem.  I changed it in game and wasn't able to get it to work, so I quit and tried again and still couldn't get it to work.  I then went to try Caarie's method but when I open up any of the .xml files it opens up Big Bang Mancala (which came on the Macbook).  I am not too computer literate as it is so I'm not sure what to do from that point.