Burning a database to CD-R forces it to be a read-only unless you are using a CDRW system.
You do not want to use the CDRW for a active database also.
IF you have copied a file to the CD, it by default will be read-only. You burning S/W may have a switch to burn it as read-write, however, why not just un-protect it when it is copied to a hard drive.