How to use FTDI to program Lilypad Arduino?
"Access is denied" this looks like you should at least restart your computer after you installed the FTDI driver if you have not already.

Run Arduino IDE as Administrator and also make sure you are logged into an Administrator account in your windows login.

If all this fails this means another application is using that com port you will need to figure out what could be using that com port another instance of Arduino IDE opened? Etc

If all else fails restart your computer with the usb unplugged, login, open arduino IDE and plug in your usb and select the com port.

Edit: You can also try changing the USB port you are currently using for another one, this will also change your com port to a new number