jQuery dialog popup behind my blog content. How to fix

I have this problem I have dealing with for a while now. My dialog appears to pop up behind my blog content. here is a screenshot.
http://wsoplugins.com/wp-content/uploads/2012/04/Capture.png
can someone help me fix this?
It pops up behind the header content to be specific. The other content below seems fine.
thank you so much.

.ui-dialog{
 
 position: fixed;
 z-index: 99999;
 
 }
 

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