Like Brian said, and what has been posted on here many times is almost all usb to serial converters that you can buy dont seem to work with the IFI equiptment and FIRST software. Dr. Joe Johnson found one last year that worked very well and was recently reccommended by IFI to use. You can find the IFI thread below along with the specs for the converter.
http://www.ifirobotics.com/forum/vie...highlight=bafo
BF-810 from Bafo Technologies