Curious Unmount Error

I received a recorded CD that had drivers copied from the original corrupt floppies.

To check what is on the disc, I attempted to read it in Mac OS X. The disc reads fine, but any attempt to eject it results in "The disk "XXX" wasn't ejected because one or more programs may be using it."

It doesn't matter if I even accessed it with any program, it just refuses to eject after being mounted. lsof returned nothing. What's going on here?

Help would be appreciated.

No, the Force Eject function ejected it fine.

My question is more along the lines of why it was busy, if nothing was accessing it. I can replicate the problem simply by inserting the disc, it's like it hangs just by being mounted.

Very strange.