Hi!
The plugin Flickr Set slideshows is causing the problem. It triggers the following error:
Uncaught TypeError: Cannot read property ‘length’ of undefined
in the following file: http://dev.tramasolutions.com/paliativos/wp-content/plugins/flickr-set-slideshows/flickr-set-slideshows.js?ver=4.3.1
line 82:
if ( $( ‘select[name=photoset] option:selected’ ).attr( ‘value’ ).length …
This code is executed on all of the back-end pages, so it might cause further issues as well. Unfortunately there is nothing I can do to ajax search pro to prevent this issue, it’s entirely caused by Flicker set slideshows.
Try temporary deactivating the slideshow plugin until you configure the search, but I recommend notifying the slideshow developer about this problem, as it may cause issues with other plugins/themes which use select drop-down boxes.