I got SQL0902C error message when backuping database.
I can backup each tablespace except syscatspace.
I tried reorg all tables in syscatspace and restart DB2 instance,but the problem remained.
I also use db2dart to inspect database and tablespace architecture and cannot find anything wrong.
I am using DB2 V7.1 + FP5 on AIX 4.3
Please check the following from db2diag.log

2004-10-20-19.30.30.579064 Instance:db2inst1 Node:000
PID:60172(db2bm.183516.0) Appid:none
buffer_pool_services sqlbDMSDirectRead Probe:790

DiagData
2003 9078 0002 0000 0000 078a 0000 0ffe ..x............
0000 0000 0078 2000 0000 0001 0000 0000 .....x .........
477b 1200 2003 90d8 G{.. ...


2004-10-20-19.30.30.732859 Instance:db2inst1 Node:000
PID:60172(db2bm.183516.0) Appid:none
buffer_pool_services sqlbDMSDirectRead Probe:86
DIA3801C buffer pool logical error

ZRC=0xFFFFF102

2004-10-20-19.30.30.852829 Instance:db2inst1 Node:000
PID:60172(db2bm.183516.0) Appid:none
buffer_pool_services sqlbDMSDirectRead Probe:86

Obj={pool:0;obj:0;type:0} State=x0 Parent={0;0}, EM=0, PP0=0 Page=6016 Cont=0 Offset=6017 BlkSize=12

Data TitleQLB_OBJECT_DESC PID:60172 Node:000
0000 0000 0000 0000 0000 0000 0000 0000 ................
0000 0000 0000 0000 0000 0000 0000 0000 ................
0000 0000 0000 0002 0000 0000 0000 0000 ................
0000 1000 0000 0008 0000 0000 0000 0000 ................
0000 0000 0000 0000 ........


2004-10-20-19.30.31.086555 Instance:db2inst1 Node:000
PID:60172(db2bm.183516.0) Appid:none
buffer_pool_services sqlbDirectRead Probe:820
DIA3801C buffer logical error

ZRC=0xFFFFF102

2004-10-20-19.30.31.175915 Instance:db2inst1 Node:000
PID:60172(db2bm.183516.0) Appid:none
buffer_pool_services sqlbDirectRead Probe:820

Obj={pool:0;obj:0;type:0} State=x0 Parent={0;0}, EM=0, PP0=0

Data TitleQLB_OBJECT_DESC PID:60172 Node:000
0000 0000 0000 0000 0000 0000 0000 0000 ................
0000 0000 0000 0000 0000 0000 0000 0000 ................
0000 0000 0000 0002 0000 0000 0000 0000 ................
0000 1000 0000 0008 0000 0000 0000 0000 ................
0000 0000 0000 0000 ........


2004-10-20-19.30.31.378604 Instance:db2inst1 Node:000
PID:60172(db2bm.183516.0) Appid:none
database_utilities sqlubreaddms Probe:9

DiagData
0000 1788 ....


2004-10-20-19.30.31.497759 Instance:db2inst1 Node:000
PID:60172(db2bm.183516.0) Appid:none
database_utilities sqlubreaddms Probe:11

DiagData
0000 ..


2004-10-20-19.30.31.587244 Instance:db2inst1 Node:000
PID:60172(db2bm.183516.0) Appid:none
database_utilities sqlubreaddms Probe:12

DiagData
0000 078a ....


2004-10-20-19.30.31.676497 Instance:db2inst1 Node:000
PID:60172(db2bm.183516.0) Appid:none
database_utilities sqlubreaddms Probe:13

DiagData
0000 0ffe ....


2004-10-20-19.30.31.766180 Instance:db2inst1 Node:000
PID:60172(db2bm.183516.0) Appid:none
database_utilities sqlubreaddms Probe:8

DiagData
ffff f102 ....


2004-10-20-19.30.31.875990 Instance:db2inst1 Node:000
PID:60172(db2bm.183516.0) Appid:none
database_utilities sqlubreaddms Probe:8

DiagData
ffff f102 0000 0002 ........


2004-10-20-19.30.31.986428 Instance:db2inst1 Node:000
PID:60172(db2bm.183516.0) Appid:none
database_utilities sqlubreaddms Probe:2208

ffff f102 0000 0002 ........


2004-10-20-19.30.33.363776 Instance:db2inst1 Node:000
PID:183516(db2agent (ACHDB)) Appid:*LOCAL.db2inst1.041020113001
database_utilities sqlubcka Probe:0 Database:ACHDB

Backup terminated.