Even though you installed the last version of VideoLAN VLC, it may happen that you are not able to read DVDs that have a copy protection.
The trick to get this to work is to install the libdvdcss library (which is not in the official repositories).
You can find this library on the ATrpms.
To install the library:
wget http://dl.atrpms.net/all/libdvdcss2-1.2.10-5.fc13.x86_64.rpm http://dl.atrpms.net/all/libdvdcss-1.2.10-5.fc13.x86_64.rpm yum install libdvdcss-1.2.10-5.fc13.x86_64.rpm \ libdvdcss2-1.2.10-5.fc13.x86_64.rpm