thickbox error

Hi,
I get the following error :

Uncaught TypeError: Object [object Object] has no method ‘live’ thickbox.js:23
tb_init thickbox.js:23
(anonymous function) thickbox.js:16
f jquery-latest.pack.js:1
p.fireWith jquery-latest.pack.js:1
st.extend.ready jquery-latest.pack.js:1
xt

This error causes the not display of a form created with gravityforms!

Teh url of my site page with error:

Thanks a lot