[SOLVED] How to remove strange character on home page after installing Atahualpa 3.5.

I've installed Atuahalpa 3.5.1 for the latest version of Wordpress, in a windows server.

There is a problem with the article extract in the index/home page - it has a strange character (appears as an empty square in IE, or a black diamond with question mark in Chrome).

Example:-

" it’s� ‘El Dorado’. � It conjures ". How to get rid of this character?

If you click the link to see the full post, these characters do not appear. How to remove?