JQuery UI Blackberry Curve Issue Modal Dialog

I am creating a mobile site using asp.net and I am using JQueryUI Dialog in my application, but after its implementation it does not work on Blackberry Curve, but the same code works on Blackberry Bold. I don’t know what could be the problem, so please take a look at my code and update me, what should I do to get it working on the blackberry curve ...

<input type="image" id="imgBtnHelp" src="../Images/Help.png"  onclick="return openPopup();" /> // button

<div id="PnlHelp" class="csPnlHelp" style="display: none;"> // My Div Tag
<uc1:ucHelpControl ID="ucHelpControl1" runat="server" /> // My UserControl
</div>

<script type="text/javascript" language="javascript"> // Javascript function
//<![CDATA[
function openPopup() { $('.csPnlHelp').dialog({ width: 460 }); return false; }
//]]>
</script>