I have the same problem on all my Linux systems with OpManager 6 SP1, they all return a CPU usage of -1%. This is because the command OpManager uses does not work.
One system (Fedora 2) returns just text.
root@host [~]# top b n 1 | grep 'CPU[0-9]* states:' CPU states: cpu user nice system irq softirq iowait idle
another (Fedora Core 4)
[root@suse ~]# top b n 1 | grep 'CPU[0-9]* states:' [root@suse ~]#
returns nothing because the text is not found. Any advice ? Can we even change these commands, but that would be a bit hard as I don't know what OpManager is expecting back ?