jQuery Grid Plugin - jqGrid

I'm working with two tables, one containing schools, the other years for the schools. I'm trying to select a school then set the url for the editGridRow function to parse the php. This is the code to add a year to a school:

$(”#addyear”).click(function(){ 
    bb = jQuery(”#schools”).getSelectedRow();
    alert(bb);
    if( bb != null ) {
    jQuery(”#years”).editGridRow('new',{
        height:100,
        width:200,
        reloadAfterSubmit:false,
        closeAfterAdd:true,
        closeAfterEdit:true,
        drag:true,
        modal:true,
        url:'setdata.php?s=2&sid='+bb,
        afterSubmit: function(server_data, posted_data) {
            result = server_data.responseText.split(”;”);
            //alert(result[1]);
            if (result[0] == “success”)
                return [true,"",result[1]];
            else return [false,"Error inserting row"];
        }
    }); 
    }
    else {
        alert(”Please select a school to add years to.”);
    }
});

And this is the php used to update it:

“INSERT INTO `tblYears` (`Year_ID`,`Sch_ID`,`Year`) VALUES (NULL,'”.$_GET['sid'].”','”.$_POST['Year'].”')”);

I can get the script to insert the row into the database, but the problem is with the getSelectedRow function. When I click to Add a year the alert displays the correct ID for the school. This is fine the first time, but if I select a different school then click to Add, the alert displays the correct ID, but the bb variable still contains the previously selected School.

It appears that the ID parsed using bb is retained from selecting the very first school, all years will then be inserted into the first selected school.

Am I missing something here? I'm racking my brain trying to figure this out.