Problems with su/csh on Ultrix 4.0/DECstation 5000

[Eric M. Boehm]

I have run into a problem out of the blue. Suddenly, our DECstation 500
won't let me use su to switch to another user. I get the following error
message:

getwd: can't open .. -- can't start new shell

This happened suddenly. Also, after rebooting the machine, su may work
once or twice and then give the error message. This also screws up
commands I have in crontab -- they do not get run. Lately, even commands
running as root in crontab weren't being run. I even went so far as to
redo the Ultrix installation. That did not help. 

Any suggestions would be greatly appreciated. Please respond (if by
e-mail) to boehme at unvax.union.edu.

Thanks in advance.

--
Eric M. Boehm
boehme at unvax.union.edu
boehme at union.bitnet