What works

The Setup.exe file in the Maplestory directory works in Wine. You can setup screen frequencies using "setup.exe". The logo displays, the window with messages displays and you can click on any buttons that come up.

Successfully got the patcher to download the new needed files.

I've installed the Korean Font package to be able to see error messages. After installing Korean font package you should be able to see all error messages. So far I have seen Initialization error (114), Connection Cancelled (350) and Unable to Connect to GameGuard Server(340) - (latter happens when internet connection is disabled or down).
If you do not install korean fonts you will see garbage.

What does not
Gameguard initialisation.

What was not tested
Gameplay

Additional Comments

More info about the error codes can be found here : http://www.maplesea.com/support/gameguard.aspx#04

Of particular note are these sections of the website : 

"Q.It takes too long to load the game, and at last, displays Error code 114 and game is closed.
	
1. 	There could be a program that might be taking up too much CPU resource. Or, the video driver or sound driver might be out of date. Please scan for any virus and spy-ware, and update all drivers to the most recent versions.
 
2. 	The user might be running an anti-virus software that is too heavy for the particular system(Norton 2005, McAfee, VirusBuster, etc.) Please open the settings of the application, and disable any unnecessary features like internet monitoring, outlook monitoring, script monitoring."

"error (114) - Failed to initialize GameMon. Try rebooting or closing possible programs that can cause a collision."

Could it be possible that the sound - unsupported midi - is getting in the way of running MapleStory? (error message for midi after running MS via Wine:  fixme:midi:OSS_MidiInit Synthesizer supports MIDI in. Not yet supported. )