Help with iPhoto suddenly crashing after update?

Hi,

If anyone could please help me, I would appreciate it tremendously. All of a sudden, whenever I launch iPhoto it tells me to upgrade. When I click upgrade, it quits. It was working fine until the last update, now this. Any suggestions?

Thanks in advance!
Cheri

P.S. Also, I've somehow scrambled my mac's ability to download. It gives me an error message that users/counter/desktop/CNYkZz9y.pdf.part could not be saved because I can't change the contents of that folder??????