A lot of times this error occurs if you do not follow the installation instruction to the letter. In otherwords usually you do not want to plug the device in until after the driver is installed. If you plug the device in before the driver is installed windows will install generic drivers that may not work and even if you install the proper drivers after that there will be problems. This happened to me with a Canon scanner and what I did was to remove the scanner from the PC, use System Restore to go back to a point prior to the device being plugged in, and then install the driver package and reboot the PC before plugging in the device (you can also try uninstalling the drivers from Device Manager if you can find them, then remove the device connection and reboot). Then viola it worked. Twain drivers can also be a problem if they do not get installed properly or at all. You might want to look at the contents of the install disc to see if you can manually install them before you do your reboot after installing the device drivers just to be sure.