Personal Code? maybe the product key?
if you use steam start up steam go to Library, then instead of left clicking "mount and blade warband, right click it and select view CD key, and type that key into the box.
If you are getting an Incorrect Authorization key, try restarting your computer/router.
If you keep getting that message thingy. Try starting the launcher then checking the box "repair"
If all of the above things don't work, then I have no idea and I'm sure someone else can help you!
Good-luck!