/dev/scd0 in use?

[David Krider <david davidkrider com>]

I'm trying to copy a CD (the burnt iso's, actually) from my CDR to my
CD-RW. I'm getting the following ``Error trying to open /dev/scd0
exclusively ... retrying in 1 second.'' I'm even trying to do it as
root. This was never a problem before. Everything's SCSI. fuser shows
that nothing has it. What's this mean and how do I fix it?

dk