fixed error in google chrome: Cannot call method 'find' of undefined jquery.bxslider.js:819.

using public method startAuto() throw this error in google chrome:

Uncaught TypeError: Cannot call method 'find' of undefined jquery.bxslider.js:819
updateAutoControls jquery.bxslider.js:819
el.startAuto jquery.bxslider.js:1222
(anonymous function)