Two problems

Hello,
I'm running postgreSQL on BSDI-3.1
And I have two questions:
1. if i grant permissin to table to someone, then I can't do this that table
before I grant
permission to myself:

ser=> \z

Database    = ser
 +-----------------------+--------------------------+
 | Relation              | Grant/Revoke Permissions |
 +-----------------------+--------------------------+
 | userd_daily_stat      |                          |

ser=> select * from userd_daily_stat;
   uid|           money|work_time|  rec_date
------+----------------+---------+----------
(11 rows)

Then, I:

ser=> grant select on userd_daily_stat to someone; -- grant to existing user
CHANGE
ser=> select * from userd_daily_stat;
ERROR:  userd_daily_stat: Permission denied.
????????

2. Sometimes it happens then vacuuming return:
NOTICE:  BlowawayRelationBuffers(userd_bank, 2): block 3 is referenced
(private
0, last 0, global 1)
pqReadData() -- backend closed the channel unexpectedly.
        This probably means the backend terminated abnormally before or
while pr
ocessing the request.
We have lost the connection to the backend, so further processing is
impossible.
  Terminating.

What does it mean ? It seems to me that the reason is vacuuming then
somebody working
whith database but it impossible to find when no one connected.

Thank you,
---------------------------
Sergei Chernev
Internet: ser@nsu.ru
Phone: +7-3832-397354