TIP: DO NOT PLUG THE CABLE INTO YOUR COMPUTER FOR THE FIRST TIME WHILE CONNECTED TO THE INTERNET. In Windows 7 at least, windows will automatically connect with windows update and download a prolific driver when you plug in the cable. This driver does not work and you will get the Error 10 code. If this has happened to you, uninstall the driver. And proceed as below.
Do this the first time plugging in the cable or after uninstalling a non-working driver as above:
Download the following driver...and ignore the fact that it is labeled a 'vista' driver:
Unzip the file and DISCONNECT your computer from the internet. Install the driver from the file you just unzipped. Plug in your cable and you should be good to go. Reconnect to the internet.