AIX monitoring

Hello,

I'm trying to monitor some AIX servers via SNMP, but I have some problem, for example,
even if I'm able to browse the CPU utilization with the command :

HOST-RESOURCES-MIB::hrProcessorLoad.1 = INTEGER: 0
HOST-RESOURCES-MIB::hrProcessorLoad.2 = INTEGER: 0

I tried to add the corresponding resource monitor (snmp, cpu utilization via HOST-RESOURCES) but OpManager complains about the monitor is not responding