Question:
AVR USB Programmers give FTDI DLL error. Why?
Answer:
This means that the USB driver is not installed. The Installer for the software will pre-install a Windows certified USB driver. When the programmer is plugged into USB port, Windows will automatically install the driver and display messages at the bottom right of your screen.
If you still get problems, go to Control Panel > System > Hardware > Device Manager and check driver status.