i can't find local disc (C:)
Drive (C:) is your computers main hard drive. Go into the Start Menu, and then into My Computer, or Computer depending on your Operating System. Under "Hard Disc Drives" you should see one that says "(C:)" along with the brand of your computer in the name. Click on that. Then go into Program Files (or Program Files (x86) and find a folder named "Gravity", go into it, and then go into the folder named "Dragon Saga" and you should see a file named "Patcher", delete it. Then find the file named "patcher2" and rename it to "patcher".
After that, run Dragon Saga like you normally would and you shouldn't get the Korean Error.