Can’t Edit Posts with WordPress 2.6.3

So tonight I went in to edit several of my posts.

When I open up a post, and try to edit some text or add a class to an image, and then click Save – NOTHING happens. The changes don’t stick and it reverts back to the un-edited version.

I have never had this problem before – but just tried it with multiple posts and it does the same thing each time.

I can write new posts with no problem. I just can’t edit them.

Please help.