Just after downloading New wz files and replacing em i have an error: "error code -2005532292 unknown error 0x8876017c". ;_;
When do you get this error, when starting the game? Do you get to the login screen? What operating system do you have? Not enough information to assist.
I am pretty sure this is a registry problem. You will need to uninstall the game completely, then run a registry clean up too such as http://www.piriform.com/ccleaner and then reinstall the game.
Make sure you put the new files in the mapleroyals folder, not the maplestory folder. The simplest solutions are often overlooked.