To give an update, rather than provide all the information that Cyberlink requested (as I don't really have time for it now), I opted to do another reinstall.
This time, I did a complete uninstall, then installed from the retail disc.
I first had to update to build 2024 (09/01/2011), then install build 2608 (03/07/2012), avoiding the on-screen update to 3318 which caused the problems.
Download link : http://www.cyberlink.com/support/powerdvd/patches_en_US.html
Everything back to normal, with the exception of playing newer Blurays like 'Skyfall'.
I'll get around to gathering all the info at a later date.