postgres 8.2 doesn't start after ubuntu upgrade

Hello,

I recently upgraded from Ubuntu 8.04 to 8.10. After the OS upgrade I
choose to upgrade software as well (all quite automated in ubuntu).
Previously I was running postgres 8.2, but now I have postgres 8.3 (and
hopefully 8.2 as well).

I can run 8.3 and see the dbs (the default ones only; not mine) with psql.
But when I try to start 8.2 nothing happens:

$ /etc/init.d/postgresql-8.3 start
* Starting PostgreSQL 8.3 database server
[ OK ]
$ /etc/init.d/postgresql-8.3 stop
* Stopping PostgreSQL 8.3 database server
[ OK ]
$ /etc/init.d/postgresql-8.2 start
$ /etc/init.d/postgresql-8.2 stop
$

You can see I get no response when trying to start 8.2. What can I do?

To complicate matters I was using pg_dumpall to daily backup the db and
then used rdiff-backup to keep increments. For some reason on August 1,
2008 pg_dumpall went from 50MB output (correct) to a few lines (!?). So I
can't simply restore to 8.3 (the last one is from six months ago :(. I do
have an image of the hard drive (using partimage) from before the upgrade,
but that would be getting pretty desperate to have to go back there.

Bryan