I tried with differen themes, found some made for wp 2.7, and they are working but I'm missing some things in the sidebar.
So I tried to remove those <div> tags and when I movev them from the now obvious post is all worked. But with the post above everything is fine, without div tags. So I made another new post, didn't entered any div tags and the image is centered. So only one post will have that image go left, but it's fine, as long as new posts work fine.
Thank you very much man, your post helped me a lot!