jquery blockUI plugin not working when a div is updated...

jquery blockUI plugin not working when a div is updated...

i am putting a sample code.. please let me know whats the issue.
  1. function searchAndUpdateContent(searchCriteriaForm) {
        searchCriteriaForm.ajaxSubmit( {
            beforeSubmit : function() {
                jQuery("#searchCriteriaContainer").block({message : "Searching..."});
            },
            success : function(returnValue) {
                jQuery("#searchCriteriaContainer").unblock();
                jQuery("#searchResultMainContent").html(returnValue);
                jQuery("#searchCriteriaContainer").block({message : "Search Complete. Click to unblock..."});
                jQuery('.blockOverlay').click(function() {jQuery("#searchCriteriaContainer").unblock();});
            },
            error : function(request, status, errorThrown) {
                alert("Error during Search!!!");
            }
        });
    }














The problematic code line is :
  1. jQuery("#searchResultMainContent").html(returnValue);
Once, the code hits this line, block/unblock code stops working.
If i comment out the above line.. the code works fine. searchResultMainContent and searchCriteriaContainer are independent div elements. I am not getting why updating content of one div will impact the blocking feature of another div.

Thanks,
Avinash