if the dvd won't read a cd-rw do i have to use a dvd to make a boot disk for evoltion x

Yes, using DVD-R should work if you use brand name media like Sony,Philips...

make sure your have made a Xbox ISO not a PC ISO and try to put a dummy file.

It all depends on what DVD drive you have. And also what brand and all that good stuff. YOu could use a CD-RW of a different brand, you could use a DVD-R and DVD+R of some certain brands. I have a samsung drive and used a Fujifilm DVD+R and it worked the first time.