[ADMIN] how to fix "missing chunk number 0 for toast value xxxxx"???

[dennis]

Dear All

pls somebody help me.
I run into a problem "MISSING CHUNK NUMBER" .
I have tried all solution. but all doesn't work.

------------SYSTEM INFO-----------------
bash-3.2$ cat PG_VERSION
8.2

bash-3.2$ postmaster --version
postgres (PostgreSQL) 8.2.14

-------------ERROR MESSAGE----------------
ERROR:
bash-3.2$ pg_dumpall >20100211.out
echo:
pg_dump: ERROR: missing chunk number 0 for toast value 8059494
pg_dump: COMMAND：COPY public.usersessiontable (serverid, sessionid,
data) TO stdout;
ut
------------Tried Soluctin-----------------
method 1:
reindex table usersessiontable;

method 2
select reltoastrelid::regclass from pg_class where relname
='usersessiontable';
RETURN
pg_toast.pg_toast_87664

reindex table pg_toast.pg_toast_87664;

method 3:
reindex INDEX usersessiontable_idx;

method 4:
vacuum db

but the all above method doesn't work for me.

thanks