No X Windows on PowerBook G3 Help!

[befu <befu@gmx.net>]

Hi,

I have a problem installing XFree86 on my PowerBook G3 (Wallstreet, May
1998, 256MB). I newly installed the kernel v.2.2.20-powermac through floppy
disks. I downloaded the X window package (v. 4.1.0-16) with tasksel. Now
when I boot up (using BootX), X doesn't start but gives the following error
messages:

    Fatal server error: no screens found

and    (WW)    ATI: PCI/AGP Mach64 in slot 0:17:0 could not be detected
            (EE)    No device detected

in the XFree86.0.log file.

I tried to modify the file XF86Config-4 with the command

dpkg-reconfigure xserver-xfree86

but nothing helped.

Has anybody an idea what I am doing wrong?
What shall I do to get debian to work?

TIA
Befu