Uncaught TypeError: n.slides.on is not a function - Flex Slider Views

An Error occurs, when using flexslider with thumbnail slider option set -

Uncaught TypeError: n.slides.on is not a function
at Object.setup (jquery.flexslider-min.js?rokrtw:5:3987)
at Object.init (jquery.flexslider-min.js?rokrtw:5:3074)
at new $.flexslider (jquery.flexslider-min.js?rokrtw:5:21487)
at HTMLDivElement. (jquery.flexslider-min.js?rokrtw:5:22661)
at Function.each (jquery.js?v=1.4.4:33:46)
at $.fn.init.each (jquery.js?v=1.4.4:26:388)
at $.fn.flexslider (jquery.flexslider-min.js?rokrtw:5:22464)
at HTMLDivElement. (flexslider.load.js?rokrtw:42:17)
at Function.each (jquery.js?v=1.4.4:33:46)
at $.fn.init.each (jquery.js?v=1.4.4:26:388)