Hey!
I have problem, I have bought board in last time, it was sucessfully works, but only on Arch Linux ( interesting is that it wasn't work on Ubuntu! ;D ). On Windows XP and Windows Vista i still have this problem, system detect board as unknown/undefined device and I can't install drivers. ;]
Anyone have solution for it?
Edit: Board work on other PC 
FTDI provides a device driver remover for all FTDI devices. Maybe you can just clean your Windows system and re-install the FTDI driver.
That doesn't help, any other help? ;o I have not installed drivers before connecting board!
go to device manager and update the drivers for anything with a ! or a ?, then try again.
I'm getting the same issue. Though I'm not getting a response from either PC i connect it to (Windows 7 & Ubuntu 9.04). 
Is the FTDI IC fried? Is there any way to fix this without having to fork out cash for a new one?