[Plugin: FancyBox for WordPress] Fancy box doesn´t work

Hello i´ve installed de plugin and when I go to the images in a post and click one it doesn´t work.
the site is http://www.comocontrolarunaeyaculacionprecos.com/
I´ve already try to desactivate the other pluggins.
My theme is arras. I´m sure it´s works because I´m reading a book about wordpress and the autor installed this pluggins perfectly.
PLEASE HELP ME.
FRANCA

http://ww.wp.xz.cn/extend/plugins/fancybox-for-wordpress/