The mother of all permissions problems

Hello group...

For the first time in my life I am seriously considering reinstalling Linux just to get rid of a configuration problem I cannot understand.

It started out, believe it or not, with the attempt to install vendor drivers for a cheapbutt Samsung ML-1610 laser printer under SuSE Linux. They commendably offer a binary driver with a pretty GTK installer. It doesn't work at all, though, so I uninstalled it with their uninstaller program. And that was when it started...

I am now unable to configure any printer even in the normal YAST dialog; CUPS keeps complaining

lpr: unable to print file: client-error-request-value-too-long

I have already learnt that this message is misleading. A combination of "strace yast2" and "morevar-log-cups-errorlog" tells me that there is really a permissions problem:

# grep ^Evar-log-cups-errorlog E 25-Sep-2006:23:33:59 +0200 ReadClient: Unable to write 27816 bytes tovar-spool-cups-00000000: Bad file descriptor

pid 2278 chown32("-var-spool-cups", 4, 7) = 0 pid 2278 chmod("-var-spool-cups", 0710) = 0 pid 2278 chown32("-var-spool-cups-tmp", 4, 7) = 0 pid 2278 chmod("-var-spool-cups-tmp", 01770) = 0 pid 2278 open("-var-spool-cups", ORDONLYONONBLOCKOLARGEFILEODIRECTORY) = 0 pid 2278 open("-var-spool-cups-00000000", OWRONLYOCREATOTRUNC, 0640) = -1 EACCES (Permission denied)

OK, so user 'lp' cannot write tovar-spool-cups, but why? It seems to set the 710 permission itself and then fail mysteriously...

But when I tried to investigate further, I received a much nastier shock:

# su - lp su: warning: cannot change directory tovar-spool-lpd: Permission denied su:bin-bash: Permission denied

# man su execve: Permission denied

That's right. Root cannot su to `lp', and *root cannot read man pages* anymore, although my user account has no problem. What the %$&-#! can possibly be going on here?

-- No animal was harmed in the making of this post.