No blue star for SNMP

Hello,

i don't see the blue star in the corner of my win2000 and win2003 servers for SNMP!
but i get CPU %, Memory % and Disk % over SNMP.
at some server i also see in the asset details the RAM and Disk capacity,
but i can't see the network interfaces, when i rediscover an interface, then it says: "interface added successfully" but there no interface after.
I also set the correct login passwords and the public community
I have version 6010

Could anybody say, what i have to do?

Thanks