--- uc_upsell_core.inc.orig	2010-06-03 14:24:43.000000000 +0200
+++ uc_upsell_core.inc	2010-06-03 14:25:02.000000000 +0200
@@ -207,12 +207,20 @@ function uc_upsell_get_associate_nids($s
     $random_nids = array();
     $filter_query = implode(",", array_merge($ary, uc_upsell_get_cart_nids()));
 
-    $randoms = db_query("SELECT `nid`
-                FROM {node}
-                WHERE `status` = 1
-                AND `type` IN ('". implode("','", uc_product_product_types()) ."')
-                AND NOT nid IN (". $filter_query .")
-                ORDER BY RAND()");
+    if ($filter_query) {
+      $randoms = db_query("SELECT `nid`
+                  FROM {node}
+                  WHERE `status` = 1
+                  AND `type` IN ('". implode("','", uc_product_product_types()) ."')
+                  AND NOT nid IN (". $filter_query .")
+                  ORDER BY RAND()");
+    } else {
+      $randoms = db_query("SELECT `nid`
+                  FROM {node}
+                  WHERE `status` = 1
+                  AND `type` IN ('". implode("','", uc_product_product_types()) ."')
+                  ORDER BY RAND()");
+    }
 
     while ($random = db_fetch_array($randoms)) {
       $random_nids[] = $random['nid'];