Here is where I would start, open iTunes and see if you can drag the file into the library, if you can then it should play. The default preferences usually are set to open iTunes automatically so I bet this is a strange sort of file. Where did you get the music?
Anyhow if you can get it into iTunes and it still won’t place, go into the advanced tab on the menu bar and tell it to convert the selection to mp3, then it should go.
And if it doesn’t, I’m with sakura, I will come stand under you window too!!!