First, take a look at the /dev/cdwriter link for the actual device it points to. In my case is /dev/sg0
Note that your burner device is owned by root and belongs to the group "disk", so the non-root users who can burn cd's must also belong to that "disk" group. This can be added in redhat-config-users, select the user and, in "properties" go to "groups", check "disk" group for the non-root user.
Also give group permissions to the device.... something like:
chmod 660 /dev/sg0
Finally, take care of the disk label length when burn CDs with nautilus, It must never have more than 31 characters, and that's not checked, it simply gives up.