try this:
Disconnect the programming cable from both the computer and scanner.
Download and
then run this file from FTDI, the manufacturer of the chips on the cable:
http://www.ftdichip.com/Drivers/CDM/CDM%202.04.16.exe
Plug in the programming cable to your computer. You should see a notification that the cable has been found and shortly afterwards a notification that it is ready for use.
During the process the notifications will indicate which com port it is using or you can go to the Device Manager and see the port number. Make sure you are using that port number in your software.
After drivers finish installing, insert the plug into the scanner (Do not use the short adapter cable.)
This has worked on my Vista computer and on my XP computers.