Tabs stopped working

Hi, i’ve a strange problem: on one of my sites the tabs stopped working, but just on one single page!

not working example: http://www.prilisauer.at/reservierung/

but it’s working here: http://www.prilisauer.at/rieglerhuette/

i also tried to remove all the content on the page, to no avail. it seems to be related to the page layout i select from the theme, do you have any hints on this?