SNMP v3 user creation

Hi all,
 
I'm new to the net-snmp
 
I would like to create snmp v3 user to access the SNMP stack.
 
I tried to use snmpusm to create the user and got the following error:
net-snmp-5.2.1.2>apps/snmpusm -v 2c -c private snmp-server create USER rwusr
Error in packet.
Reason: noCreation (That table does not support row creation or that object
can not ever be created)
Failed object: SNMP-USER-BASED-SM-MIB::usmUserStatus.""."USER"
 
Any idea what may be wrong??
 
Thanks
 
Connie