Hi dolt61,
There should not be any write-protection on a cd-rw if you are using the same program (such as In-CD) which produced it in the first place. If you no longer have the program installed on your computer, then you will not be able to write to that disc any longer. Also, if someone else wrote to the disc in their computer, your computer may not be able to write to the same disc because the different drives are not quite universally standardized.
You could however, copy the contents of the disc over onto a CD R/W of your own making and then you should have no problem writing to it in the future.
Hope this helped.
Cheers!