Oh lawd. Someone call the cavalry. There has been a HUGE inflation in the amount of dupers at the moment.
According to random leechers in game, they say certain sites that are affiliated with hackers have released a public version of map crash. Now everyone and their mothers are currently attempting to crash the map. Hotspots like Henesys and the FM should be avoided at this time.
Surprisingly Nexon has recently put out a service announcement that a maintenance would be put into effect shortly to address the issue.
For anyone that is having trouble logging into the game or getting the dreaded Error 5 code understand that it is NOT your fault. Its just the Maple client being shut down on you by map crashers.
Just stay away from the mentioned hot spots and you should be fine. For those of you stuck on those maps ~_~ hopefully Nexon will have you guys fixed up in no time.
Stay tuned for more info on the situation. In the mean time just search some forums or something.