All you have to do is to update the firmware of the console and download any additional packages which might be available for either of the two games.
In most cases, whenever you are running a game that supports a later firmware on a console with a not-up-to-date firmware, it tends to be problematic.
On the other hand, the disc could be faulty in such a way that you cannot see with your ordinary eyes.
If the above solution doesn't help you out, then you might have to call the company and see if there is any known problem with your batch of discs.
Hope this was helpful?