Ive always had problems with the file that ive yanked from aros.org. I cant remember specifically what that problem is. The file is good, i beleive it's extension was messed up. And i used IE. maybe it was a tar.gz but came in as a .tar or something. Anyway, i found out what it was by looking at it in a hexeditor. or maybe it's extension is tar.gz or .tar or what ever, but it's really just a plain ISO image. It's something simple like that.
But like dude above said, aros max is waaaaay better, get that instead.