Hello my name is XXXXX XXXXX X will be happy to help you today.
Make a back up of your Iphoto library. Now, no matter what you do, you're covered.
Go to your Pictures Folder and find the iPhoto Library there. Right (or Control-) Click on the icon and select 'Show Package Contents'. A finder window will open with the Library exposed.
Look there for a Folder called 'Import' or 'Importing'. That one in your picture...
Drag it to the Desktop. *Make no other changes*.
Start iPhoto. Does that help?
If it does then look inside that folder on your desktop. Does it contain anything you want? If not you can trash the folder.
Let me know if this fixes your problem by giving me a good rating below. If this has not fixed the problem please let me know and I will research this problem more. Thank you,