If you received your ACTIVvotes after October 24, 2007, you probably received the new 2.4 Ghz votes. You can tell the difference between these and the "old" votes in that the 2.4 Ghz votes requires the use of a hub that is attached to a USB port on your computer.

Activating the new 2.4 Ghz votes is different from the older ones. Instructions for doing so can be found here...
Quick Start Guide - Activote 2.4 Ghz, downloaded from Promethean World's support page.