Full Screen In Vnc Viewer

Hi,

I'm a complete newbie on Suse Linux and on Linux since I first used it this week.

I work in a research center and we just bought a server with SUSE server 64bit and run it from windows XP in a VNC Viewer window. When we go full screen there's always a 4cm wide black frame on the screen. Do you know how to get a true full screen. When I try to change the resolution I get this erreor message "The X server does not support the XrandR extension ..."

Do you know how to fix this problem.

Thanks
Pilou