Note: Most Xboxes DO NOT need the Xbox tweak.
It is also considerably harder than a mod chip because it is sooo easy to knock the laser assembly out of alignment while doing this.
You may well be burning those CD-RW disks in an incorrect manner.
Check out the burning tutorial on the home page. Also try burning the downloaded ISO directly at the slowest speed possible.
If all else fails you could disconnect the Xbox DVD reader from the IDE chain (but leave the power & yellow cable on!) and hook up your PC's DVD reader instead. This would permit you to install Evolution-X onto the hard drive.
Also remember that if your intent is to place games on the hard disk you will absolutely need a new larger replacement drive. The bigger the better, up to 136 gigs!