In case a comparison of permissions might help:
| Program | Permissions | New Permissions |
|---|---|---|
/usr/bin/cdrdao |
0755 root.root |
4710 root.optical |
/usr/sbin/cdrdao |
0755 root.root |
4710 root.optical |
/sbin/cdrdao |
0755 root.root |
4710 root.optical |
/usr/bin/cdrecord |
4755 root.root |
4710 root.optical |
/usr/sbin/cdrecord |
4755 root.root |
4710 root.optical |
/sbin/cdrecord |
4755 root.root |
4710 root.optical |
/usr/bin/growisofs |
0755 root.root |
0750 root.optical |
/usr/sbin/growisofs |
0755 root.root |
0750 root.optical |
/sbin/growisofs |
0755 root.root |
0750 root.optical |
With these permissions my k3b works as expected.