You actually don’t need to type anything into the file itself. Just save the text as is, as a .bat file. You just have to drag the file you want to convert and drop it on the .bat file. It will output your new files into the same directory as the original file.

Edit:
I’ve updated all of the files at the previous links above. They should work better, as they will let you drag and drop multiple files onto the batch file, and will create a new directory called “AAC” at the path of the original files.

Let me know if you can get this working.