Correct me if I'm wrong but most CCD images of emu's and homebrewed stuff have been made selfbootable. You get the choice between selfbootable images and the plain files, which are not selfbootable. I once had a failing one, and I downloaded the discjuggler image (CDI) and burned it with Alcohol, and it did work. So you could try that.
No offence but I got the feeling it's about a downloaded image
There is a homebrew app for scrambling/descrambling the 1st_read.bin so that might be the solution. Also the disc needs to be written in two tracks and I've never even tried to take the plain files and get it selfbootable myself, just because I'm not that experienced with burning multiple tracks that way. Ofcourse you could get yourself a bootdisc.
You're going to need to burn another disc anyway, so in case you get more images like that you can use the same bootdisc. If you need advice on which bootdisc to get just ask, I've got enough experience with them.