my friend had the same issue.
This same error happend to my friend and we resolved it.
What you need to do is check in your folder and look for any .xml files and delete them. I believe the files i was told to delete was called Config.xml. If you don't find any don't worry about it. If you do not find any then what you need to do is open up the task manager with ctl+alt+del then go to the processes tab. Once you have the processes tab up you neeed end all programs that are non system, non local service, and non network service. Also make sure that you do not end explorer.exe. Also ventrilo and xfire do not cause this error to occur because i run them in the background with no issues. We surmised that there is some background program that conflicts with the game causing it to present this error. If you figure out exactly which program it is that would be a great help. Obviously the program conflicting is not needed to run the computer so we don't really know which one it is. If you do end all your background programs and it is still giving you problems i would recommend going to the s4 league website and going into the chat. Nfected and yokoimo helped me resolve this issue and they seem to know more about what might be messing up the game, although they do not know exactly which background program conflicts with the game. I really hope this advice fixes your program! Happy S4ing!