if you are on 64bit machines, you've got to be in test mode and have digitally signed the drivers through the DSEO software...
on 32bit machines, or 64bit, for that matter... if the install doesn't go right, or something is malfunctioning, go to 'devices and printers'. if the cart is plugged in and working right, it will appear as funtional here. if there is anything wrong with the driver install, you'll get an error in this section. don't bother troubleshooting it or auto-fixing anything.... its all got the be done by hand.
so, first is to uninstall the drivers from the device. unplug the cart and everything. then, open dseo and go into test mode (if you already aren't). and, restart your comp. next, digitally sign the files you need. and, again, restart your comp. then, plug in the cart and do the manual install.
my first install of the drivers went pretty smoothly after i got off my dell XPS (these machines, 400 series dell's in general, have issues running some drivers it seems). but, i deleted my files accidently, and the reinstall i had to do a couple times. same procedure each time. but, it only worked after the third try about. and, i haven't had issues at all since.