image lib showing but not working

Editing a new (or existing) blog post, clicked on media to insert a picture from my image library. Contrary to other recent posts, I see the library, click to second page of images, click SHOW to see and edit the image. That’s where the functionality ends. If I try to save the image (change description), or if I try to insert it into my post, the media window remains open but displays my home page. Nothing is inserted, nothing is changed.

I tried using twenty-ten theme, disabled all widgets, etc. No change.