Shed Doors Not Closing

I had a 12'x10' wooden shed built this last July. The doors closed fine. Now the left door (this door is closed first) closes fine. But when I close the right side door it won't close and be flush. I could maybe pound it in but that won't fix the problem. It has piano type hinges, I don't know if this matters. I tried to tighten the hinge screws but it seems they are stripped. They are holding okay but if I try to tighten them they just spin. I took one screw out, filled the hole with toothpicks and put the screw back it but it stripped too. I need to fix this but I don't know how. I've included a picture. Once again, thank you for your expert help in advance. Attachment 38738 (http://www.doityourself.com/forum/attachments/garages-garage-door-openers-work-shops-sheds-breezeways-carports/38738-shed-doors-not-closing-shed-2.jpg)