Probs with upgrade from IPhoto 8.1.2 to 9.5

I bought the new IPhoto version 9.5 to upgrade mine 8.1.2 and it shut down immediately after I tried to use it. It could not update the library. I saw a post on the apple support page, that I should install 9.1. before I update my library. But then I got the message, that I first have to use 9.x ...so it´s a circle....what to do? I am using Mackeeper on my macbook pro, but I don´t think that this has to do with my anti virus program as someone mentioned before. Any suggestions very welcome :/

I also bought 9.5 and had no problem installing it and the library appeared to update successfully, but music was lost in all my slideshows and I can't recover it. I also can't play music in new slideshows. "Play music during slideshow" is checked, the source is iTunes, I select a song, click "Choose," no music. I'm on iTunes 11.1.1 and it's working properly. It appears the link between iPhoto and iTunes is broken. Very discouraging. Is there any way to restore the previous version of iPhoto?

Bob D.