By just including (but not using) the JQuery 1.3.2 js some IE6 users get an ActiveX warning. By switching back to 1.2.6 those users are no longer getting the ActiveX message.

I think this means that the problem is with this line:

div.innerHTML = ' <link/><table></table><a href="/a" style="color:red;float:left;opacity:.5;">a</a><select><option>text</option></select><object><param/></object>';

Or at least that is the only place I can find where JQuery 1.3.2 might cause IE6 to instantiate an ActiveX object.