I can't anymore open My Iphoto Library located on an ext disk

My Iphoto Library, located on an ext disk, suddenly ask to rebuilt. I did it, but a problem occurs. Now I can’t anymore open this library from Iphoto (I can see it, but when I click on the open button, nothing occurs). I try to double click on this library. it begin to import in Iphoto, but a problem occurs again and it stop.