musicmonkey: dont know what is going on here, are you on a mac?
the playlist editor is a single executible file 'PlayList1.1.1.exe' if you have something else like a .zip file or a .rar file then you will need to uncompress it first with 3rd party software like 'winrar' (free download). If you are using a PC and the file is a .exe file and it still doesent know how to open your in real trouble.
By the way, dont know if you have done this but you need to download and
install the .net framework, not just save the file.