iPhoto 9.2.3 will not open after update.

I had to reintall system software on my older macmini back to mac OSX 10.6.8., iPhoto 9.2.3 worked before I had to reinstall. I tried restoring from "Time Machine" and I got the same message "iPhoto cannot be opened because of a problem. Check with the developer to make sure iPhoto works with this version, etc;. Well it worked before. I then downloaded iPhoto 9.2.3 and reinstall and I get the same error warning. What am I doing wrong.