Why do I get an error message while opening programs?

Hi!

After upgrading my computer, I got a message saying that there was a problem opening iPhoto and other programs such as iMovie, Spotify etc. When I click on the icon for iphoto on my dock, it will not open. I just get an error message, saying the exact same thing:

"iPhoto cannot be opened because of a problem. Contact the server to make sure that this program is possible to use with this version of Mac OS X. You may have to install the program again. Make sure that you have installed all the avalible upgrades for the program and for Mac OS X."

I had to translate it into english, so the spellings and the language is probably not right, but I hope you guys understand.

My computer is a 10.7.5 version, and I tried to install iPhoto 11´. That was when all the problems started.

Please, can anybody help me to get my programs to open again?