iphoto no open in my mac

when i tried open iphoto in my mac, this program no open.

and appers a msg:

" Your iphoto library is either in use by another application or has become unreadable: Shut down and restart your computer, and then open iPhoto again. If the problem persists, try rebuilding your photo library. To do this, quit iPhoto, and then reopen it while keeping the Option and Command keys pressed. You can also try restoring your photo library from a backup."

i nedd help for this problem.

Alex Burgos.