My iphoto library won't show when trying to select a photo for other programs?

I am having a problem when I try to select a photo or itunes song in Imovie or other programs. I get a window with grey lettering that says: "Open Itunes to populate this list" or "Open iphoto to see photos from your iPhoto library in this list. I have tried relaunching programs and nothing appears. Seemed to start happening a while back after one of my system upgrades.