微小的滚动条出现JavaScript错误(JavaScript error with Tiny Scrollbar)

我将TinyscrollBar添加到我的Wordpress网站，并且在页面加载时出现以下错误：

oViewport.obj[0] is undefined

我确信我首先包含了tinyscrollbar.js文件，然后才能打电话

if (jQuery('#execphp-3 div')){ jQuery('#execphp-3 div').tinyscrollbar(); }

可能是导致错误的问题是什么？

编辑：tinyscrollbar运行的HTML：

<li class="widget-container widget_execphp" id="execphp-3"> <h3 class="widget-title">Talking NanoChannels</h3> <div class="execphpwidget"> <div id="scrollbar1"> <div class="scrollbar" style="height: 347px;"> <div class="track" style="height: 347px;"> <div class="thumb" style="top: 90.8106px; height: 256.189px;"> <div class="end"> </div> </div> </div> </div> <div class="viewport"> <div class="overview" style="top: -123px;"> <ul class="wrap masoned" id="simplepie" style="position: relative; height: 683px;"> <li title="" class="box col1" style="position: absolute; left: 0px; top: 0px;"> <h4> <span class="twitter"></span> <a href="http://twitter.com/EreiItamisy/statuses/87518699866701825">      5th International Conference on Nanochannels, Microchannels, and Minichannels: Puebla, Mexico - June 18-20, 2007: http://amzn.to/jutpBp</a> </h4> <span class="corner"></span> </li> </ul> </div> </div> </div> </div> </li>

I added TinyscrollBar to my Wordpress site, and I'm getting the following error when the page loads:

oViewport.obj[0] is undefined

I made sure that I first included the tinyscrollbar.js file, and only then do I make the call

if (jQuery('#execphp-3 div')){ jQuery('#execphp-3 div').tinyscrollbar(); }

What could be the problem that's causing the error?

EDIT: The HTML that the tinyscrollbar is running on:

<li class="widget-container widget_execphp" id="execphp-3"> <h3 class="widget-title">Talking NanoChannels</h3> <div class="execphpwidget"> <div id="scrollbar1"> <div class="scrollbar" style="height: 347px;"> <div class="track" style="height: 347px;"> <div class="thumb" style="top: 90.8106px; height: 256.189px;"> <div class="end"> </div> </div> </div> </div> <div class="viewport"> <div class="overview" style="top: -123px;"> <ul class="wrap masoned" id="simplepie" style="position: relative; height: 683px;"> <li title="" class="box col1" style="position: absolute; left: 0px; top: 0px;"> <h4> <span class="twitter"></span> <a href="http://twitter.com/EreiItamisy/statuses/87518699866701825">      5th International Conference on Nanochannels, Microchannels, and Minichannels: Puebla, Mexico - June 18-20, 2007: http://amzn.to/jutpBp</a> </h4> <span class="corner"></span> </li> </ul> </div> </div> </div> </div> </li>