table corrupted

Hi everybody,
Can someone help me how to repair the problem below, I'm using Postgres
8.2.5:
- after appeared the erros below in selects, vacuum and dump in one table:
2009-10-16 16:07:06 BRT 192.168.0.87 ERROR: could not access status of
transaction 29024764
2009-10-16 16:07:06 BRT 192.168.0.87 DETAIL: Could not open file
"pg_clog/001B": No such file or directory.
2009-10-16 16:07:06 BRT 192.168.0.87 STATEMENT: select ...
2009-10-16 16:11:47 BRT 192.168.0.29 ERROR: invalid page header in block
462821 of relation "..."
2009-10-16 16:11:47 BRT 192.168.0.29 STATEMENT: select ....
I created the file pg_clog/001B with 256kB of /dev/zero
That resolve the problem with vacuum but began other error in selects and
dump to the same table ended all connections and stay up after showing the
error:
2009-10-19 13:50:03 BRT LOG: server process (PID 1544) was terminated by
signal 11
2009-10-19 13:50:03 BRT LOG: terminating any other active server processes
2009-10-19 13:50:03 BRT 192.168.0.253 WARNING: terminating connection
because of crash of another server process
2009-10-19 13:50:03 BRT 192.168.0.253 DETAIL: The postmaster has commanded
this server process to roll back the current transaction and exit, because
another server process exited abnormally and possibly corrupted shared
memory.
2009-10-19 13:50:03 BRT 192.168.0.253 HINT: In a moment you should be able
to reconnect to the database and repeat your command.
Was habilited the zero_damage_pages option then executed selects, vacuums,
and dumps but not changed...
Was identified 2 register that if refered cause error.
The BD was restored in backup server with 8.2.7 and executed vacuums ok but
select and reindex crashed...
Instaled 8.3.8 version and used pg_dump but error
And then the select below show the problem where the codentrega from where
clause differ from select answer:
LOGIST=# select codentrega from entregas where codentrega='9879622';
codentrega
------------
z879622
(1 registro)

Any idea?