Since downloading the latest update, my Mac has crashed directly to desktop twice: once while on the final loading screen, and once during a solo battle. In both cases the error message returned was the same:
Game Error 
The game client was passed invalid command-line parameters.
Any suggestions for dealing with this problem gratefully received.
Playing on a 3.2 GHz Intel Core i5 iMac with 8 GB memory, running OSX 10.8.5.