iframe not loading

hi,
i've included an <iframe></iframe> into a jquery tab but it's loaded
only once, source http://www.qualitydesign.ro/test/jquery/ click on
the "one" and "two" and "three" buttons and than again 1, 2 and 3 and
the iframe it's not completely loaded. i've try this link in firefox,
opera, ie8, safari and chrome. where is the problem?
thanks.