.blockUI plugin centering issue

.blockUI plugin centering issue

Hi! I'm using the .blockUI plugin from here ( http://jquery.malsup.com/block/#download ) and for some reason my dialog box is not centering in the page. 

Here is my pop up code/message:  

  1.     $('#StreetNumberNameSearch').click(function () {         $.blockUI({             fadeIn: 1000,             message: '<h1 style="padding:10px 20px 5px 20px; color:#003366; font-size:18px;">To Search by Street Number &amp; Street Name</h1><p>Enter the street number and street name without designators such as West, North, Avenue, Lane, Road, etc.</p><p><b>Example:</b> 1234 Main Street would be entered as:</p><p><img src="/images/search_help/streetSearch.jpg" alt="" title="" /></p><p>&nbsp;</p><p><img src="/images/round_red_close.gif" class="floatLeft" alt="" title="" style="padding: 0 5px 10px 0px; margin: 0;" /><a href="#" id="closeStreetNumberNameSearch">Close This Window</a></p>'         });         $('#closeStreetNumberNameSearch').click(function () {             $.unblockUI();         });     });

I found this thread (  https://forum.jquery.com/topic/blockui-centering-the-dialog-window ) but I can't seem to figure out how to incorporate it into my code.

I appreciate any help, thanks in advance!!