My xbox iso won't boot up

Please help i'm going nuts.
I've done a lot of reading of these forums and they've been great but now i'm having problems that i can't find help on.
I have had my xbox modchipped and played a copied game on it.
I've been able to FTP from my xbox to PC using Flashfxp then create an iso using Qwix.
My problem is that when i burn the iso using DVD Decrypter or Nero the game won't boot on my xbox. I've been using TDK DVD+R, they burn ok but won't boot and when i tried TDK DVD-R it says "Cannot Write Medium - Incompatible Format" and just ejects the disk.
My computer is only 6 months old and the burner is: NEC DVD+-RW ND-6500A.
Can anyone please help me get these games working?

 

It's probably the media itself- try the process with DVD +R etc till you find one that works.

 

Yea dude try the Taiyo Yuden and Verbatim DVD-R they are really good. ANd Slow down the Burn speed.

 

Hey Guys, thanks for the help.
Finally got it working last night, the problem was that i couldn't burn to a DVD-R so i flashed my burner with the latest firmware so now it burns to them.
I burnt the ISO to a TDK DVD-R and the xbox read it fine.

 

The good news .. if you upgrade to the nextgen xbox.. is that discs will likely be made self booting like in the days of DreamCast