Hi and welcome to the forums!!!
This is a bit tricky, I keep on messing up my landings myself, because of some little twitches, I forgot to clear up!
I'll try to make up a list, why rudder may not work properly: (maybe someone will enhance it in time)
- You may have [NumLock] disabled
- You may have Multiplayer-Chat window open (which steals the focus of the [Enter]-key)
- You may have some other text-window open (same as above)
- You might not use the standard-keyboard-layout, maybe some keys are "misplaced" (especially on Mac-keyboards)
- You may have [CapsLock] enabled (which switches your NumPad to adjust view, as if you would press [Shift]+[NumKey])
I hope, you can figure out, what is the case for you!
Don't hesitate to ask here again, if your problems don't get solved by this! Given some patience, we'll figure it out! Feel free to search the wiki and the forums in the meantime for similar problems, you'll learn quite a bit on the way!
Here might be a start:
http://wiki.flightgear.org/New_to_FlightGearCheers and happy flying!!!
chris