11.2 x86-64 cd to a cd fails

I am still in the process of rebuilding my laptop with openSUSE 11.2 x86-64. I downloaded a large application tar.gz extracted 500M of app to disk copied it to cd with K3B and verified the cd. I then deleted the tar.gz. I browsed the CD with dolphin (/media/expc/… I then start a terminal su to root cd /media/expc and get an error stating the the file or directory does not exist or is inaccessible. If I go back to my own account I still can’t cd to /media/expc. From /media ls -l lists expc as being readable by everyone and in any case I can browse it with dolphin.

The CD is fine. I mounted it by hand on /mnt as root and then installed the application without problem. Going back to the original way of loading and mounting the cd reproduces the problem

Has anyone any idea what is happening here?

Could be that by default cds are readonly in linux.