ok this wont fix it, but it will get you back on maple again.
Create a new user logon for windows, and copy across the maple install file to the shared folders.
Then switch logins to the new one and install maple again, overwrite old install if you want.
Then play the game on that logon, it will work that way, while you try to figure out whats wrong.
Would this work for my problem too? It's diffrent...I downloaded .51 from scratch but it still won't work. It's the same error :/ Like a stupid never ending server check.