dpkg doesn't work offline?

["W. Borgert" <debacle@knorke.in-berlin.de>]

Hi,

is it possible to install a package using dpkg without
sitting at the console, i.e. offline?  The system is
"stable".

The problem is with a PC somewhere in the desert connected
via ISDN/PPP:  A friend wants to update the ISDN package.
Of course, if he tries to dpkg -i isdnutils_xyz.deb, the
connection to the PC would drop.  He tried to use dpkg with
`at' and `cron', that is firing the `at' job, logging out
and logging in after the `at' job.  A similar at script is:

#!/bin/bash

PATH=/usr/sbin:/usr/bin:/sbin:/bin:/usr/bin/X11:~/bin
export PATH
/usr/bin/dpkg -i /usr/local/archive/bsdgames_2.5-4.deb
sleep 60

Unfortunately, it didn't work.  There was always an error
message mail:

Subject: Output from your job        2

dpkg-deb: wait for gzip -dc failed: No child processes
dpkg: error processing /usr/local/archive/bsdgames_2.5-4.deb (--install):
 subprocess dpkg-deb --control returned error exit status 2
Errors were encountered while processing:
 /usr/local/archive/bsdgames_2.5-4.deb

What did he do wrong?  Are there any chances to dpkg a new
isdnutils package from remote?  Note: He can't definetily
not go and do anything at the console, the machine is a few
hundred kilometres away...

Thanks in advance,
-- 
W. Borgert <debacle@debian.org>