[jQuery] BlockUI in IE 7 does not unblock

[jQuery] BlockUI in IE 7 does not unblock


perhaps you can help me, I have the following code:
     var waitDiv;
     var selectMachineDialog;
$(document).ready(function() {
waitDiv = document.getElementById("waitDiv");
selectMachineDialog =
document.getElementById("selectMachineDialog");
$.blockUI(waitDiv, {border: '2px solid #FFC000'});
if(haul_id != null){
loadHaulRequest(haul_id);
} else {
getHaulTypes();
getHaulMachineLocations();

document.getElementById("customer_id").focus();
}
$.unblockUI();
});
The blockUI works exactly as desired in FF but in IE it never clears
the blocked message
Thanks
Ben