Cannot post images — Asks me to log in

I have looked at the sticky post about media uploader problems, , tried a couple of the suggestions, and no luck.

My problem is that when I use the built in uploader, it uploads an image, but then goes to the log-in page. But it will not let me log in.

I also tried the single image uploader and it will upload the file, but it will not save it with a post.

This happened spontaneously. I cannot figure out what happened.

Short of reinstalling WordPress, does anyone have any ideas as to what happened, and what I can do abpout it?