The maplestory.exe is packed with ASProtect. PEiD or ExeinfoPE can detect it. Especially, ExeinfoPE shows unpacking information. It is written that 'try Stripper v2.13 beta 9 by syd or Ollydbg.exe with plugin Aspr2.XX_unpacker_v1.0E by VolX OR DecomAS by PE_Kill 2011.04'.
I use the following softwares.
ImpREC, i.e. Import REConstructor, 1.7e -
link1,
link2