You have to erase existing CD-RW data before the CD can be rewritten.
Erase the last session only.
$ cdrw -d cdrom0 -b session
Erasing just the last session with the –b session option is faster than erasing the entire media with the –b all option. You can use the –b session option even if you used the cdrw command to create a data or audio CD in just one session.
Erase the entire media.
$ cdrw -d cdrom0 -b all