VNC & RENDERING

[centaure domain]

Hi all,
i've got a Mandrake 9.1 with ICEWM and VNC 3.3.7

when i'm connecting directly from my desktop, all X apps under icewm are working.

BUT, when i'm connecting fromVNCclient, i've got a error message : 
[user@user user]# konqueror 
loading required GL library /usr/X11R6/lib/libGL.so.1.4.500
kbuildsycoca running..
loading required GL library /usr/X11R6/lib/libGL.so.1.4.500
Xlib: extension "RENDER" missing on display":00.0".
Xlib: extension "RENDER" missing on display":00.0".


is VNC support rendering ? or any idea to fix this ?