[Image: http://puu.sh/aoBhx/0ee6faf128.gif]
Try turning DEP for client.exe and/or mabinogi.exe off?
http://windows.microsoft.com/en-us/windows7/Change-Data-Execution-Prevention-settings?SignedIn=1
is mabi installed through steam?
Looks like a modded launcher. Uninstall the mods and wait till they are updated.