Database Corruption??

Can anyone help? My pgsql problem manifests itself as follows.......

1) After psql'ing into a database, there is a table which has 3 fields
which cannot be selected from, instead
the following error occurs:

e.g. select fieldname from mytable;

FATAL: unrecognized data from the backend. It probably dumped core.
FATAL: unrecognized data from the backend. It probably dumped core.

Then I have to \q and go back in.

The same happens when selecting * from mytable;

You can do a \d to get the table description, and all other tables seem
to be ok.

2) On doing a pg_dump of this database, the following error occors:

e.g. pg_dump -o dbase > dumpfile

resetting connection
SQL query to dump the contents of Table mytable did not execute
correctly. After we read all the table contents from the backend,
PQendcopy() failed. Explanation from backend: 'Error return detected
from backend, but attempt to read the message failed.'.
The query was: 'COPY mytable WITH OIDS TO stdout;
'.

Does anyone know how to rescue my data??
Are there any corresponding bugs with PostgreSql??
Is there any diags stuff to help??
How can I determine exactly what bit of the table is corrupt??
The select version(); does not work either.

any answers??

cheers
Joe.

--
Joe Cleave, FrameStore Ltd
joe(dot)cleave(at)framestore(dot)co(dot)uk