crash Xserver debian lenny

[kevin]

Hello,

I installed a debian lenny on a pc i386, for a school I manage.
This pc is intented to be an applications server, so I installed as I 
usually do for etch: xorg, xfce, xdm (we use old pc configured as X 
terminals), and then all the configuration stage for using the nis 
server, nfs server, ad so on.


When I boot the machine, everything is OK, and I get the xdmcp chooser 
screen, displayed by the "primary xdmcp server", which gives all the 
avalaible applications servers of the lan.

Then I choose as server the pc itself, which is a normal procedure with 
etch.
I should then get the login window of xdm, but I only get a grey screen 
typical of X, or, coarsely half time, the X server crashes and I get 
back to tty1.

tty1 displays a backtrace which first line is:
0: /usr/bin/X11/X(xf86SigHandler+0x7e) [0x80c91fe]

and last line is:
8: /usr/bin/X11/X(FontFileCompleteXFLD+0x21d)  [0x8073a81]

I don't know how to use this information.

Anybody can help?

Thanks.