Network Usage Alarm

Hi, we recently set up alarms for Metric Network Usage. It sometimes shows (like shown below) usage far over 100 percent. How can this be? Is this not telling me how much of the network is being used? It is an ESX 3.01 system.

I suspect it might be because we have 4 nics teamed together for the VMware host and it does not know how to handle that. Is this a reasonable explanation?

Thanks for your help.

Target: esx2.xxxxx.xxx

Old Status: Green

New Status: Red

Current value:

Basic Alert - (State = Connected OR Metric Network Usage (Average/Rate) = 529%)

Alarm: Basic Alert

( OR )

Description:

Alarm Basic Alert on esx2.xxxxx.xxx changed from Green to Red