that means when was the agent first installed on the client? Thanks
You could try looking at the FrmInst_<systemname>.log - it is usually under C:\Windows\Temp\McAfeeLogs. Each time the agent is installed or upgraded this log file is appended.
Depending on how your policy is setup, you could also look in the control panel, programs and features, currently installed programs listing to see the date it was installed.
A quick way to get there is to type: appwiz.cpl in the run box.