I have the same problem with my WordPress 3.5.1. I have all my pictures in my library but when I try to add media in a post or on a page the media library tab is blank.
the first screenshot is the blank media library
the second is an error that pops up if I try to upload a new image
https://minus.com/lJnRklaKEMHWT
https://minus.com/lpZwepPdSGkwU
