I have found the solution. We can basically let windows do the work for us.
To install CDM drivers for an FTDI device under Windows 7, follow the instructions below:
If no suitable driver is automatically found then the following procedure should be followed.
Press the Windows start button to bring up the start menu and select “Control Panel”.
From the Control Panel window select System.
At the next screen select Device Manager:
In the Device Manager window there will be a device (AFE5808) with a yellow warning symbol to indicate a problem ie no driver installed. The text next to this device will depend on the device attached.
Right click on the device to bring up a menu.
From the displayed menu select “Update Driver Software…”
This then displays the option for an automatic search or a manual search.
Select the first option to browse automatically.
When the installation has finished a completion screen is displayed.
Press Close to close this window and go back to the Device Manager Window.
The Device Manager will still show a device under Other Devices but in addition to this there is a new entry under Universal Serial Bus Controllers as the USB Serial Converter. This indicates the bus layer of the driver is installed. Installing the Virtual Com Port layer of the driver is almost a repeat of the last few steps.
Right click the device, from the displayed menu select “Update Driver Software…”, then search automatically.
Once this has been completed, everything should be installed properly.