If the name of the file burnt to the disk is not default.xbe, it will not boot. In order to boot, it must be named default.xbe. Change the file name, create a new .iso with Qwix, then burn it, and you should be able to boot the dash if the burn went right.
Once the dash is running off of the disk, you can then use FTP or the dash file explorer to copy the dash to the XBOX hard drive. Make sure to name the default.xbe file to one of the names that your bios looks for or it won't boot from the hard drive...