在IE8上，error: Object不支持这个属性或方法

I have jQuery for a WordPress theme I'm building. I've given up for now on testing IE6 and IE7 (layouting hell), and now I'm testing it using IE8. Every time I click on a prettyPhoto link OR a jQuery cycle link, JS gives out this error and fails to bring up the lightbox or move the slider. As usual his works fine in all the other browsers.I have jQuery for a WordPress theme I'm buildin