YaST2 is the easiest way to install rpm packages from the SuSE CDs. I don't know why it would suddenly stop working. Could you give details of what YaST2 does when you try to use it?
YaST2 is not the only way to install packages from the SuSE CD. That is why I asked which way you are using. Here is an example of another, more difficult, way to do it:
Suppose that you want to install a word processor called abiword. Mount the first SuSE CD using the mount command or by clicking on the CD-ROM icon on your KDE desktop. Then issue the following command:
find /media/cdrom -iname "*abiword*"
The answer that I get back when I use the SuSE 8.0 install disk is:
I can now install abiword with the following command:
rpm -i /media/cdrom/suse/gnm1/abiword-0.99.1-61.i386.rpm
If abiword is not on the the first SuSE CD, unmount the CD, mount the second CD, and use the find command on the second CD.
But installing with YaST2 is a lot easier because YaST2 takes care of the
package dependencies, removing old packages, etc. So I think that it is best to fix YaST2.