pg database hosed in update - help!

[Richard Lyons <richard@the-place.net>]

Looks like I've really done it now!

From a misplaced sense of neatness, I decided to remove the stable and testing 
sources from sources list did "u" and (after some inspection etc) "g".  It 
looked easy enough, but I got this error announcement:
-------------------------start quoted text-------
Subject: Postgresql installation

The postmaster did not start after postgresql was installed:

A database upgrade appeared to be required and an automatic upgrade was
attempted.

The automatic upgrade did not succeed; the postmaster has not been
restarted.  The commands run (by the user postgres) were:

   unset PGHOST
   export PATH=/usr/lib/postgresql/bin:/bin:/usr/bin
   postgresql-dump -ildvp /var/lib/postgres/preserve/data.7.3.2r1-5.save -Ft /
var/lib/postgres/db.out

The database requires manual intervention before it can be used.

The dump of the old data should be at:

   /var/lib/postgres/db.out

The previous database should have been preserved at:

   /var/lib/postgres/preserve/data.7.3.2r1-5.save

This was the output of the dump command:

======================================================================

Stopping and restarting the postmaster
/var/lib/postgres/dumpall/7.3/postmaster -D /var/lib/postgres/data  -p 5431 -o 
-d0
/var/lib/postgres/dumpall/7.3/postmaster: error while loading shared 
libraries: libkrb5.so.17: cannot open shared object file: No such file or 
directory
Failed to start the postmaster
---------------------------end quoted text--------

All of which looks dire, to my untutored eye.  Worse, I have no idea at all 
what to do about it.  Anyone understand this?

TIA
-- 
richard