It took me half a day to figure out how to get AVR Studio to compile on Windows 10. I kept getting errors looking for rm.exe and what-not.
Do these steps in this exact order:
1) Install WinAVR
2) Install AVR Studio 4.19 (the last version in the v4 series)
3) Place the attached mysys-1.0.dll into this directory:
\WinAVR-20100110\utils\bin
4) Load up AVR Studio, it should compile fine