Vacuum stops with misleading max_fsm_pages error

Hi there,

We're managing a database on version 8.2.3 (running Lyris ListManager email
software). I ran a 'vacuum analyze full verbose' (we haven't been able to
get autovacuum to work properly on Lyris installs so we need to run a full
vacuum every week or so, and we'd been doing some work on this machine so it
needed it). It ran happily for quite a while - about 2 thirds of the way
through the database - but then ended with the lines

INFO: free space map contains 20914 pages in 61 relations
DETAIL: A total of 14992 page slots are in use (including overhead).
14992 page slots are required to track all free space.
Current limits are: 900000 page slots, 6000 relations, using 5659 kB.

This happens (at more or less the same point but with slightly different
figures) each time I try to run this command. It also happens even if I only
do vacuum verbose.

I can vacuum individual tables quite happily but I'm not sure I can manage
to do all of them individually.

As you see, I've upped the page slots and relations (there are 131 tables in
the database in total) and it seems to me like there is more than enough.

Any ideas would be gratefully received!
Thanks
Kieran Cooper
Lyris UK