Check BootingHardDrive/Pictures/iPhoto Library/. If there are several files there, you should still be OK. I think you should have one labeled "Library6.iPhoto" but I wound'nt Delete any of them. Seems I remember this being a 'feature' of the last OS upgrade. The fix was to simply drag that "Library" folder out onto the Desktop, Log OUT/IN, and drag it back to the correct spot. Then repeat the Log OUT/IN.
You might want to check Apple's Forums, also. Uhmm, it appears you have already been there...