...or just below the free text editor on the menu is a structured editor. The trick then is to note the error, go to the latest Route Availability Document (RAD) and look up the FIR for the reason you got an error. That said, a bloke in Paris told me that the computer does generate errors that the manual editor people simply accept because they know they're wrong - LSGS arrivals for example. It's a bit of a pain in the ass, but quite satisfying when you eventually get a NO ERRORS.