I got it.
Some people had the same problem, as I could see doing a search.
To solve it, I reviewed all the posts, re-writing the text and relocating the pictures. The problem was still there, so I decided to take a look into the code from the Internet Explorer.
I found out that there was a post repeated. The problem was that the repetition of the original post was hidden, so it was blocking the charge of the rest of the items of the blog, including the menu at the sidebar.
As some admins said before: avoid pasting from MS Word.
