Atmel Flip not working

I am currently trying to create a macro keyboard with an Arduino Mega 2560.
Therefore, I have to flash the Arduino with the Atmel Flip software.

My problem is, that there are two different errors:
Either it says that it can’t find the file “AtLibUsbDfu.dll” or that that it can’t open an USB device.

Is there anybody who has an exact description what I have to do, maybe from the very beginning (installing board drivers, because I don’t really know if I have to install drivers that come with the software or the driver that I was using before i had installed Flip).

I would really appreciate if someone could help me.