Problem: keyboard not working properly, i.e. Upper-Arrow key activates the screen-shot window.
    Client-side: Ubuntu 8.10
    Server-side: RHEL-5.0
Solution: upgrade the server-side nxserver to 3.3.0
check this link.

on server-side:
(1) service nxserver stop
(2) install the newest nxserver and nxnode
(3) service nxserver start

that's it.