Yes, I also have been thinking about a bad install, but everything seemed to go well and the installer program didn't mention any problem.
I try to do all the updates that Apple proposes via the automatical update system. The yesterday's update was only for Java but that's all I remember.
LW was turning during the download of this update. I had to reboot the computer after the Java install and, surprise, LW didn't launch no more ! Of course I tried to repare authorisations, check disk, check Java preferences... Nothing helped... So I deleted my LW Pro and tried, at your recommandation, the beta version 5.2.2 Basic. And that worked well. But I didn't hear anything else about this problem on other forums, so I think I might have an incomplete install ( which seems almost unbelievable) or some other problem which I still have to find. I hate unsolved problems...
Where can I drop my remarks about the beta version ?

Have a nice day !