The uiquery plugin bgiframe (version 2.1.1) causes the following java script error in Internet Explorer 9:
jquery.bgiframe.js, line 94 character 5
In the plugin code for bgiframe version 2.1.1 was doing a regex search for "6.0" but it needs to search for "MSIE 6.0". Tillito has found the correct source.
In the bgiframe code look for:
if($.browser.msie&&/6.0/.test(navigator.userAgent)
Change to:
if($.browser.msie && /msie 6\.0/i.test(navigator.userAgent)
OR just get the source here: https://github.com/brandonaaron/bgiframe/blob/master/jquery.bgiframe.js