No Data from Cisco Router

No Data from Cisco Router

We are evaluating NetFlow Analyzer and there is no data. "No Router is currently exporting Netflow packets to NetFlow Analyzer " We configured the Cisco 2620 to export the data to port 9996 on the machine we installed NetFlow Analyzer. We have a Firewall in between that we opened up port 9996 UDP from the router to NetFlow Analyzer. Does NetFlow Analyzer need other ports open on the firewall to receive the data.