when i stop the Db2admin it worked successfully.
But when i execute db2admin start it throws an error

[db2admin@lnx7 ~]$ db2admin start
SQL4401C The DB2 Administration Server encountered an error during startup.
[db2admin@lnx7 ~]$

when i check the diaglog for the error it displayed as

2011-02-01-15.38.52.171580+330 E741792194G916 LEVEL: Severe
PID : 13626 TID : 405793680 PROC : db2sysc
INSTANCE: db2inst1 NODE : 000 DB : REPORTER
APPHDL : 0-5102 APPID: GAC93EAD.O910
AUTHID : REPORTER
EDUID : 218 EDUNAME: db2agent (REPORTER)
FUNCTION: DB2 UDB, base sys utilities, sqeLocalDatabase::FirstConnect, probe:110
MESSAGE : ZRC=0x850F0005=-2062614523=SQLO_NOSEG
"No Storage Available for allocation"
DIA8305C Memory allocation failure occurred.
DATA #1 : String, 283 bytes
Failed to allocate the database shared memory set.
The configured DATABASE_MEMORY plus smaller overflow may have
exceeded INSTANCE_MEMORY or the maximum shared memory on the system.
Attempting to start up with only the system buffer pools.
Database shared memory set size is (bytes):
DATA #2 : unsigned integer, 4 bytes
405789081



2011-02-02-11.43.02.005415+330 I741901554G1181 LEVEL: Severe
PID : 32459 TID : 3086751424 PROC : perl
INSTANCE: db2inst1 NODE : 000
FUNCTION: DB2 UDB, DRDA Communication Manager, sqljcCommConnect, probe:10
MESSAGE : ZRC=0x81360012=-2127167470=SQLZ_RC_CMERR, SQLT_SQLJC
"External Comm error"
DATA #1 : String, 11 bytes
CCI Error:
DATA #2 : unsigned integer, 4 bytes
118
CALLSTCK:
[0] 0x0493FF62 _Z16sqljcLogCCIErrorP10sqljCmnMgrPKcP12SQLCC_COND_ Thiiii + 0xF6
[1] 0x0493CE96 _Z16sqljcCommConnectP10sqljCmnMgr + 0x15E
[2] 0x0438D5CC _Z15sqljcCmnMgrInitP10sqljCmnMgrP17SQLCC_COMHANDLE _TPhjP14db2UCconHandleh + 0x3B6
[3] 0x049638D3 _Z20sqljrCreateTransportP14db2UCconHandle + 0xB1
[4] 0x0438F11C _Z23sqljrAssociateTransportP14db2UCconHandlePibP19 SQLE_SRVLST_DBENTRYS1_ + 0x54
[5] 0x04963C38 _Z20sqljrInternalConnectP14db2UCconHandlePbPib + 0x324
[6] 0x049651AB _Z30sqljrFindBestAddressAndConnectP14db2UCconHandl e + 0x53
[7] 0x04961977 _Z23sqljrDrdaArAuthenticateP14db2UCinterfaceiPj + 0x667
[8] 0x04868F59 _Z20sqlexAppAuthenticateP14db2UCinterface + 0x511
[9] 0x0495C94C _Z18sqljrDrdaArConnectP14db2UCinterface + 0x8E
[root@lnx7 instance]#

Maybe this info will help:
https://www-304.ibm.com/support/docv...id=swg21198111

thanks it was helpful