I'm using jquery 1.3.2 and having the same error , but with daterangepicker() (http://www.filamentgroup.com/lab/ date_range_picker_using_jquery_ui_16_and_jquery_ui_css_framework/).
The demo on their website is working well though. Here are the lines that triggered that error (inside the daterangepicker js component): var rpPickers = jQuery('<div class="ranges ui-widget-header ui-corner- all ui-helper-clearfix"><div class="range-start"><span class="title- start">Start Date</span></div><div class="range-end"><span class="title-end">End Date</span></div></div>').appendTo(rp); rpPickers.find('.range-start, .range-end').datepicker (options.datepickerOptions); rpPickers.find('.range-start').datepicker('setDate', inputDateA); rpPickers.find('.range-end').datepicker('setDate', inputDateB);