Illigal mode for this track?

This is something I’ve been wondering about for a while. Almost always when I burn/backup a CD with Nero I get something like this:
Burn process done successfully at 1X
Error. Illegal mode for this track

But everything seems to work fine when I try to use the backed up CD (with another exe. of course) So what’s the deal with the ‘illegal mode for this track’ message?

Maybe it is a bug, or what could be wrong is that you made somekind of configuration in NERO that does not go with that CD.