Probs with backups, please help me!

[G-SAS]

HI!

I got some Dreamcast games on CD-R and they work perfectly.
For some of them I need the Utopia 1.1 boot disc.

I also downloaded several Games with edonkey or direct connect. I burned them with clonecd nero or discjuggler 3.5. But not one single game is working. The dc tries to play some of them like a music cd and the utopia disc doesn't help.

The games are: Virtua Fighter 3tb, Heavy Metal, Virtua Cop...

What is my problem? I copied some backups with clonecd and they work. I also downloaded and burned the Utopia cd and it works, too.

Please help me I wasted 12 CD-Rs!