Sanity check for deleted vendors

src/engine/db/handlers/dbWarehouseHandler.java

@@ -200,6 +200,10 @@ public class dbWarehouseHandler extends dbHandlerBase {
             while (rs.next()) {
                 JSONObject jsonObject = new JSONObject(rs.getString("workorder"));
                 WorkOrder workOrder = new WorkOrder(jsonObject);
+
+                if (workOrder.vendor == null)
+                    continue;
+
                 submitList.add(workOrder);
             }
         } catch (Exception e) {