Problem in admin - Javascript error "vis is not defined" when saving the template

Hi,

when pressing the "Save" button in joomla back-end, Firebug displays the following Javascript error:

"TypeError: vis is undefined
visible = T3AdminLayout.t3visible(idx, vis.vals),"

The template cannot be saved and I am unable to save any new changes.

The joomla! version is 2.5.24.

Thanks in advance.