There are issues seen within the CSV files that are preventing the data from being collected. Can you get the csv file associated with whatever device you are trying to use Performance Tool on? The csv files are located \cscopx\data\gsu\_#GSUDATA#_
At Service Level View, right-click on a CallManager, Unity Server, or Gateway in PATS, then select Polling Parameters. In the drop-down box, make sure Voice Utilization Settings has "Polling Enabled" box checked.
Once this is Applied, wait for the polling period to pass (default is 4 minutes). Then you can right-click on the device, select Performance, and choose what you want to graph.
http://www.cisco.com/en/US/docs/net_mgmt/cisco_unified_operations_manager/2.0.1/user/guide/perfgrph.html