hmm, i had this same problem.. fixed it by opening my hosts file in notepad and deleting a line that had to do with maplestory.
(your driver)\windows\system32\drivers\etc
open the host file with notepad, there will be a bunch of IP address' with names next to them
DO NOT TOUCH ANY OF THEM EXCEPT FOR THE ONE HAVING TO DO WITH MAPLEGLOBAL.
delete it and save.
that's how i fixed that problem -.-