/dev/null permission denied after restore from backup

[dev.loop at gmail.com]

Hi,

I had a completely running FC4. Due to some changes I had to wipe the
partition linux was installed on. Some time later that changed back,
so there was no need to wipe linux in the first place. But luckily I
made a backup of the MBR and the linux partition.
(dd if=/dev/hda | rsh user at host "gzip -9 > backupMBR.dd.gz"   --> for the MBR)
(dd if=/dev/hda1 | rsh user at host "gzip -9 > backup.hda1.dd.gz"  -->
for the linux partition itself)

I restored everything via ssh using a knoppix cd 
(rsh user at host "cat backupMBR.dd.gz" | dd of=/dev/hda  --> for the MBR)
(rsh user at host "cat backup.hda1.dd.gz | gunzip" | dd of=/dev/hda1  -->
for the root partition)
and grub starts up fine. Also FC4 seems to start booting without
errors, until it reaches the point where it complains
mknod: failed to create /dev/null: 17
mknod: failed to create /dev/zero: 17

I checked the mailing list, and found some postings where other users
also had this error. The conclusion of that discussion was, that it is
a bug and need not be taken serious.
Since I did not change anythin in the udev rules, I wouldnt expect
that to be the cause.

Anyway, going further in the boot process some applications complain,
that they dont have the necessary permissions on /dev/null.

And when the boot process finishes, and I try to login, PAM cannot
authenticate the user. I suppose also due to the /dev/null problem.

I havent found anyone else on the list having the same problem, so I
started a new thread.

Thanks for any pointers, hints, solutions.

Cheers,
/dev/loop