snmpwalk on vacm tables returns error after agent restart due to sighup

Hi,
  I am running the net-snmp 5.3.0.1 on Redhat Linux. 
I've created a few user and vacm directives in the snmpd.conf file. After
starting the agent I executed a couple of snmpwalks on
SNMP-VIEW-BASED-ACM-MIB::vacmSecurityToGroupTable and the
SNMP-VIEW-BASED-ACM-MIB::vacmAccessTable to see the vacm configurations in
the mib tables.  I was able to see the corresponding entries.
 
When I restart the agent by sending the HUP signal as: kill -s HUP <snmpd
pid>,  snmpwalk to the same tables returns error, but the access control
still works denying/allowing access to the mibs as configured in the
snmpd.conf file.
 
The message I get is: 
SNMP-VIEW-BASED-ACM-MIB::vacmSecurityToGroupTable = No more variables left
in this MIB View (It is past the end of the MIB tree)

 
I need to stop and start the agent again for it to work.
 
What am I doing wrong?
 
Yogeeta