problem in net-snmp-5.4 !

hi there.
i have a problem in suse 11 and net-snmp 5.4
i have wrote a program in suse 10 with net-snmp 5.3 and i create a customized MIB and its works right
configuration of my MIB is like this

imports enterprises from SNMPV2-SMI ;
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mymib
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::= {enterprises 999} // 999 = mymib oid start

and now i should write this program in suse 11 that this version of suse has the snmp 5.4 package and i have configured snmpd.conf right
but it throws exception
my code is like this

snmpwalk -v2c -c public 127.0.0.1 .1.3.6.1.4.1.999
ERROR : SNMPv2-SMI::enterprises.999 = No Such Object available on this agent at this OID

i have added enterprises from SNMPV2-SMI but it doesnt recognize 999

but when id edit my command like this :

snmpwalk -v2c -c public 127.0.0.1 .1.3.6.1.4.1
ERROR :

NET-SNMP-EXTEND-MIB::nsExtendCommand.“1.3.6.1.4.1.999.1.1” = STRING: public
NET-SNMP-EXTEND-MIB::nsExtendCommand.“1.3.6.1.4.1.999.1.2” = STRING: public
NET-SNMP-EXTEND-MIB::nsExtendCommand.“1.3.6.1.4.1.999.1.3” = STRING: public
NET-SNMP-EXTEND-MIB::nsExtendCommand.“1.3.6.1.4.1.999.1.4” = STRING: public
NET-SNMP-EXTEND-MIB::nsExtendCommand.“1.3.6.1.4.1.999.1.6” = STRING: public
NET-SNMP-EXTEND-MIB::nsExtendCommand.“1.3.6.1.4.1.999.1.7” = STRING: public

it recognize NET-SNMP-EXTEND-MIB as the root

please tell me how should i configure my snmpd.conf

is 999 incorrect and should change it or another part my commands has error ?

please help!!!