Okay first and foremost you need to make sure that you have a booktype setting firmware installed on your burner (assuming your burner has one or even supports it as not all burners support the booktype setting feature). I'm not even sure if your revision supports it. No amount of software is gonna allow you to set the booktype to DVD-ROM if your burner won't even support it in the first place. I suggest spending some time digging around for firmware updates for your burner in the downloads section at
http://www.rpc1.org. As for setting the booktype with IMG Burn, once you get the proper firmware installed on your burner (assuming once again that it exists), then you can go in and adjust it manually and it should come out just fine (don't screw around with the booktype setting in DVDinfopro as it often creates more problems than it solves). Also, in IMG Burn be sure to set the layerbreak at the appropriate spot. There is alot more to creating a proper 360 image than the original XBOX and if you even screw up or miss one step you end up with a coaster, so be sure you verify every single step of the creation/backup process before you burn another disc. *EDIT* Looks like there is one.
http://club.cdfreaks.com/showthread.php?t=...age=3&pp=25