[jQuery] BlockUI in IE 7 does not unblock

[DroidCommander]

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