hi,
check Firewall (Windows firewall and if there is any network-firewall):
Ports 161,162 for SNMP Traps (161 is from CMS --> Managed system / 162 is from managed system --> CMS)
also check SNMP Service configuration on managed system and on CMS (CMS should have "accept from all hosts" managed system should have correct community string and snmp target defined)
If you need specific configuration details check:
http://h18004.www1.hp.com/products/servers/management/unified/infolibraryfm.html
if you have other questions just ask ;-)
Regards,
Ville