I don't understand why it is referencing the CD drive when you are doing an on line (network) update. Are you sure that you are using online update? Do this.
Log in as root.
Start a terminal window.
Enter the following command in the terminal window command line:
You should see the Yast Online Update (YOU) window start, initialise, look for servers, get a list of updates from the server, and then ask you if you want to proceed.