Q: I have Lion 10.8.4 and Final Cut pro 7 not opening, why?

Because it hates you. 

OK, seriously now...how did you install it? Migrate it, or install fresh from the installers?  What does happen when you try to open it?

Same to me. OSX 10.8.5, clear installation of a new mbp retina. I installed fcp studio 3 (so fcp 7, also updated to 7.0.3). When i try to run the program i doesn't start and a windows with debug information appear.

Try removing audio units plug-ins.

Reboot, then try again.

http://support.apple.com/kb/TA27428

Thanks Goldfish but the folder of Audio plug-in are already empty (the article seam to refer to X version not 7).

At the end I decide to restore the system with OSX recovery. I don't understand exacly what I did because I restore the system (I had no tm backup) but at the reboot all the program installed still there, also FCP. (And I did a restore becouse it take about 2 hour)

BTW after this "restore" FCP start correctly.