xfce and xdmcp

[kevin]

Hello,

first of all, I am not sure my title is correct, as I do not guess where 
my problem comes from.

I manage a lan in a primary French school, built up whith old pcs 
configured as X terminals. We use debian etch.

In each classroom there are several Xterms and 1 "powerful" pc (PIV 2.4 
Ghz) configured as "application server".
 When booting a pc (Xterm or not), xdmcp displays its chooser list, then 
the user chooses one application server among those which are 
avalaibles, then he logs in.

We exports home files from another server using nis and nfs.

We previously used KDE.

Now I reinstalled all the computers, (xterms and applications serveurs) 
: debian etch, kdm and xfce. Now, only xfce is installed, neither KDE 
nor gnome are installed any more.

The nfs server stays unchanged, which means the old config files for KDE 
are still unchanged in each /home/<user>.

The problem is :
* if a user sits down in front of an xterm, (then choose a server, then 
logs in) its desktop displays icons, the background is the debian 
spiral, and plugging a usb key displays an icon
* if the same user sits down in front of an application server, then 
choose *this* server, then logs in, then its desktop displays no icons, 
the background is the xfce mouse, and plugging a usb key displays no 
icon. And clicking onto "xfce parameters" displays nothing.



I tried to destroy all .kde/ and .gnome*: same problem.

Any idea ? Which logs to look at ?