Fixed in New Firmware
I had the same issue and just upgraded to the latest firmware: 3.0.0.4.376_3754
And the problem is resolved now. Also the Traffic monitor has the tab for "Internet" again as well.
I also did settings-reset to default on the router before upgrading the firmware and manually re-entered all of my settings before upgrading. I don't know if that helped or not.
Hopefully it works for you since this new firmware also resolves the big LAN-side security issue.
-Morgan