Unexpected chunk number

Hi,

On running pg_dump, I am consistently getting the following errors:

pg_dump: ERROR: unexpected chunk number 2 (expected 0) for toast
value 223327
pg_dump: SQL command to dump the contents of table "pagecache"
failed: PQendcopy() failed.
pg_dump: Error message from server: ERROR: unexpected chunk number 2
(expected 0) for toast value 223327
pg_dump: The command was: COPY meatballwiki.pagecache (page,
lastmodified, response) TO stdout;

I am running psql 8.1.4. The disk storing the database was recently
corrupted, and we restored from an old image; I appreciate this is
likely to have triggered the error. What I'm interested in is how to
fix it!

I've tried a simple `VACUUM ANALYZE FULL`, I've done `REINDEX
DATABASE foo`, and I've stopped and started postmaster (all in that
order). Nothing has helped. I've looked at the pgsql mailing list
archives, but so far can find no solution that fits; for instance, I
cannot find any tables under pg_toast., so cannot use the thread at
http://archives.postgresql.org/pgsql-admin/2005-09/msg00057.php

Any help would be most appreciated!

Cheers,
Chris Purcell