Activision support: change the amount of free hard disk space on your system by 700MB. This can be done by either installing another PS3 game (like Infamous), downloading game demos (like the Infamous demo), or downloading and removing videos from the hard drive (like videos of Infamous).
The Activision support site notes the team is working on a better solution: "We take this issue very seriously and are working to resolve this issue as soon as possible. We apologize for any inconvenience this may cause." We're sure PS3 owners will patiently wait for a patch.