I've just burnt a data CD image, but have ended up with a useless audio CD. What am I doing wrong?

Did you load the cue sheet or just the main .bin file before writing the CD? If you've bypassed the cue file stage you've probably confused your CD writing software. Because the cue file lets your software know which mode to use when burning a CD image, if you don't open this file to begin with, it automatically uses the default setting - usually it assumes you want to make an audio CD.

Another possible explanation is that your cue file could contain incorrect file location information. If this is the case you can edit your cue file to check which directory it is pointing to. If your bin file is in a directory other than the one referred to in the cue file, you have two options; you can either relocate the bin file to match the path stated in the cue file, or you can edit the cue file so that it corresponds to the directory in which your bin file is stored. It is often more practical to delete the path reference altogether, leaving just the name of the file. This way, your burning software will assume that the bin file and cue file are situated in the same directory.