Post content disppears entirely after editing

After upgrading to WP2.6 I’ve realised this grave problem with my blog – whenever I have attachments (usually photos) in my post, whenever I edit the post after publishing it and the submitting the edited person, the post content disappears entirely and what I get will be just a blank page with no content, absolutely nothing. However, restoring previous versions of the post will return the original post, but I can no longer commit any edits because if I do so, the post content will disappear again and I can only restore it again.

Have anyone encountered problems like this? I got this problem only after WP2.6. I suspect there’s something wrong with the post revision feature. Any help? Thank you!