I know perfectly well what it means.

I think the problem is the NAV database. I've been trying to go direct but have been getting the not in database message.

So, from the manual I figured out how to 'move' waypoints, without getting the not in database message.

It does seem odd what with many aircraft, an FS plan can be loaded, but try and do it manually and you'll soon discover that alot of it isn't even in the nav database.