need to check if something exists before checking its type

diff --git a/engine/lib/elgglib.php b/engine/lib/elgglib.php
index 0d1d291f03b67fd1318a479dec948726e2550e36..1469067ca57e3d5fdc96e4cf3ed368cd71d33e5f 100644 (file)
--- a/engine/lib/elgglib.php
+++ b/engine/lib/elgglib.php
@@ -424,7 +424,7 @@ function elgg_bootstrap_externals_data_structure($type) {
                $CONFIG->externals = array();
        }
 
-       if (!$CONFIG->externals[$type] instanceof ElggPriorityList) {
+       if (!isset($CONFIG->externals[$type]) || !$CONFIG->externals[$type] instanceof ElggPriorityList) {
                $CONFIG->externals[$type] = new ElggPriorityList();
        }