tightVNC ignores keyboard

Hello,

On my local network, there is one desktop with monitor and keybord. Two
other computers dont have monitor or keybord, and I (try to) administrate
them via a VNC connection. On one computer, it works well, so I think, the
firewall settings on the main computer are ok. But the other computer only
reacts to mouse input, but ignores (remote) keybaord input.

Neither of the remote computer has a firewall.
The system is SuSE 9.2
The well working computer has only minmal graphic installation, the other
one (the non working) has KDE, and the problem starts allready on KDM login
manager. Initially, it worked on KDM, but I dont remeber after wich
manipulation(s) the keyboard functionnality was lost. (It apeard after
rebooting after some days of inactivity)

Is there a configuration File for thightVNC? Or for KDM/KDE with such
setings? What could make this difference?

Thanks for any idea.

Fabio Vassalli