pg_dump: Error message from server: ERROR: compressed data is corrupt

Hi list.

Do usual pg_dump today and have got an error.

---------------------
pg_dump: SQL command failed
pg_dump: Error message from server: ERROR: compressed data is corrupt
pg_dump: The command was: COPY public.candidates (id, name, surname,
mid_name, compensation, created, birthday, updated, creator_id, updater_id,
home_region_id, home_city, home_street, other_languages, home_region_other,
edu_conformity, sex, deleted, resume_text, resume_text_index, mark, kids,
driving_license, marital_status, software_knowledge, business_contacts,
type_writing_rus, type_writing_lat, desired_duties, desired_other,
updater_name, citizenship, compensation_currency, folder_id, plus,
random_cat, temp_reg, "temp") TO stdout;
----------------------

I had 8.2.0 on Solaris 10 (SunOS server3 5.10 Generic_125101-05 ),
pg_data_dir on zfs mirrored pool. I've checked status of pool and got:

----------------------
-bash-3.00# zpool status tank
pool: tank
state: ONLINE
status: One or more devices has experienced an unrecoverable error. An
attempt was made to correct the error. Applications are unaffected.

action: Determine if the device needs to be replaced, and clear the errors
using 'zpool clear' or replace the device with 'zpool replace'.
see: http://www.sun.com/msg/ZFS-8000-9P
scrub: scrub completed with 0 errors on Tue May 29 19:46:12 2007
config:

NAME STATE READ WRITE CKSUM
tank ONLINE 0 0 0
mirror ONLINE 0 0 0
c1t0d0 ONLINE 1 0 0
c1t4d0 ONLINE 0 0 0

errors: No known data errors
--------------------------------------------------------

So it seems a drive should be replaced but pool is still functioning. I
still can copy pg_data_dir to other filesystem without any errors. And
database seems working as usual. So I guess pg_dump should work but It does
not. I've upgraded to 8.2.4 but still have the same error. Copy pg_data_dir
to another file system, start postgres with that data_dir, tried pg_dump
again but still have the error.

So the question is what should I do in order to pg_dump start working as
usual?

Thanks
Roman.