Relation 0 does not exist

Hi.

When I run SQL command, I've got the error messe 'Relation 0 doesn't exist'
and following log messages were generated.
After this error happens, I can not access database at all.

Could you kindly advise why this kind of error happens?

Regards,
y.furuse

----------------------------------------------------------------------------
---------------------------------------------------------------
[Version]
PosrgreSQL7.2.4

[SQL command]
INSERT INTO SDBA2 SELECT * FROM VHIST2 ;

[TABLE Layout]
CREATE TABLE SDBA2(
Client        TEXT,    
RESVNO    TEXT,
DEPT        TEXT,    
CUSTID        TEXT,    
DT        DATE,    
TM             INT,    
DTM             TEXT,    
RESVTM    TIMESTAMP,    
CPLTTM    TIMESTAMP,    
WTM        INTERVAL,
STM        INTERVAL,
OBJ        TEXT,    
METHOD    TEXT,    
COMTM    TEXT,    
DIAG        TEXT,    
TREAT        TEXT,    
NEXT        TEXT,    
AG        TEXT,    
AGDAYS    INT,    
AGDT        DATE,
FU        TEXT,    
FUDAYS    INT,    
FUDT        DATE,
PS        TEXT,    
PSDAYS    INT,    
PSDT        DATE,
STS        TEXT,    
COMMNT      TEXT,    
AGE        INT,
SEX        TEXT,    
OCCUP        TEXT,    
ITYP        TEXT,
ATT1        TEXT,    
PRIMARY KEY(CLIENT,RESVNO)
);


[LOG message]
Feb 25 02:30:01  postgres[736]: [1] DEBUG:  server process (pid 32278) was
terminated by signal 11
Feb 25 02:30:01  postgres[736]: [2] DEBUG:  terminating any other active
server processes
Feb 25 02:30:01  postgres[736]: [3] DEBUG:  all server processes terminated;
reinitializing shared memory and semaphores
Feb 25 02:30:01  postgres[32289]: [4] DEBUG:  database system was
interrupted at 2006-02-25 01:52:52 JST
Feb 25 02:30:01  postgres[32289]: [5] DEBUG:  checkpoint record is at
1/1DE7CE8C
Feb 25 02:30:01  postgres[32289]: [6] DEBUG:  redo record is at 1/1DE7CE8C;
undo record is at 0/0; shutdown FALSE
Feb 25 02:30:01  postgres[32289]: [7] DEBUG:  next transaction id: 6670787;
next oid: 117726
Feb 25 02:30:01  postgres[32289]: [8] DEBUG:  database system was not
properly shut down; automatic recovery in progress
Feb 25 02:30:01  postgres[32289]: [9] DEBUG:  ReadRecord: record with zero
length at 1/1DE7CECC
Feb 25 02:30:01  postgres[32289]: [10] DEBUG:  redo is not required
Feb 25 02:30:11  postgres[32289]: [11] DEBUG:  database system is ready
Feb 25 03:00:00  postgres[1006]: [4] ERROR:  cannot open segment 1 of
relation pg_statistic_relid_att_index (target block 858666545): No such file
or directory
Feb 25 03:30:00  postgres[2452]: [4] ERROR:  cannot open segment 1 of
relation pg_statistic_relid_att_index (target block 858666545): No such file
or directory
Feb 25 04:00:00  postgres[3896]: [4] ERROR:  cannot open segment 1 of
relation pg_statistic_relid_att_index (target block 858666545): No such file
or directory