1. Never put the USB cable first before installing the drivers.
2. If you did so rollback the position by System Restore and try again.
this time put the usb cable only when the rconnect installation says so.
3. If nothing works out , might be the driver is mismatched (in grey market cables) even you got the driver cd.
you can check it easily by yourself and can fix it (by editing the driver .inf file)
very easy
Please download ftdi usb viewer from web site
usbviewftdi.zip
You can also view in the properties page of the unknown device of device manager
note down pid and vid
open the driver .inf file and look if the file have the same entry i.e pid and vid
vid is standard Vendor ID
pid is product id of that vendor
if those entry doent match it means the driver you have got is not right.
either serach for the right driver or can try to edit the .inf file
change the entry of pid and vid to the entry u found in device manager usb cable (unknown) property
akash