http://bugs.winehq.org/show_bug.cgi?id=26782
--- Comment #6 from Chris H chrishylands@gmail.com 2011-04-17 13:59:33 CDT --- The executable will crash under windows, linux, or os x if it is not pointed to a server. Double clicking the icon or simply launching it as 'client.exe' will cause it to crash. This is the way that the developer has chosen to run the game.
If you look at the how-to on the linked appdb page, you will see instructions which show that you need to either point the client.exe towards a server through a web-browser or command line argument. This is the exact same behavior as in Windows and will allow the game to be run properly.