jquery .sortable() on <div>

I believe the following fiddle is what you're after: http://jsfiddle.net/GA4Qs/13/

jQuery sortable needs to be applied to the parent element containing the elements you want to be sorted.

$('#psP').sortable({placeholder: "ui-state-highlight",helper:'clone'});

Also you didn't close your divs in the right place.

<div style="position: relative;" class="sortable">        <span class="stepNum inset">1</span>        <textarea placeholder="Escribe que hay que hacer en este paso" class="step valid"></textarea></div>

Not

<div style="position: relative;" class="sortable">        <span class="stepNum inset">1</span>        <textarea placeholder="Escribe que hay que hacer en este paso" class="step valid"></textarea><div style="position: relative;" class="sortable">

You're turning .sort into the sortable, when .sortable() should be called on the container of the items you want to sort. What your code does is create 5 separate sortable lists.

Switch to selecting based on the parent container, and it works:

http://jsfiddle.net/vRCp8/1/

This one is working fine for me. I changed your selector to use the class name"nubeT"

$(function() {    $('.nubeT').sortable({        placeholder: "ui-state-highlight",        helper: 'clone'    });});​

http://jsfiddle.net/GA4Qs/11/