Req: Help!

I've created my Utopia boot disk and that correctly loads on the DC. However, when I put in the disc burned from the .ISO file, the DC just churns and churns away never loading the game. I've tried to burn .ISO files to both 74 and 80 min. discs (don't know if it makes any difference). Anyway, anybody have some input to possible reasons for my burns not working? (besides me being a retard)