fix onboarding bugs

app/ics/api/engine/retrieve_warehouse.php

@@ -17,6 +17,11 @@
         $answer['output'] = $wh->getWarehouseList($type, $sku, $id);
     }
 
-    $answer['success'] = 1;
+    if (empty($answer['output'])) {
+        $answer['success'] = 0;
+        $answer['message'] = 'No warehouse found. Please go to <b>Inventory → Warehouse</b> to create your first warehouse before using this page.';
+    } else {
+        $answer['success'] = 1;
+    }
     exit(json_encode($answer));
 ?>