!!!!problem with mssql monitoring

using mib browser ,i tried to monitor mssql2000 on a server that i already added snmp service and sqlserver agent . this is the result

mssqlSrvTable : success
mssqlSrvInfoTable : success
mssqlSrvConfigParamTable : success
mssqlSrvDeviceTable : success
mssqlDbTable : NOT success !!!
mssqlDbInfoTable : NOT success !!!
mssqlDboptionTable : NOT success !!!
mssqlDbDeviceTable : NOT success !!!

In mssqlDbInfoTable that i seriously need to monitor ,i try to get an mssqlDbInfoDataSpace but it s not work , this is an error message.
Request failed or timed out. Response PDU received from 10.1.92.35
Error Indication in response:
A general failure occured
Errindex: 1
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

what s the problem ? Please help!!