Index: includes/common.inc
===================================================================
RCS file: /cvs/drupal/drupal/includes/common.inc,v
retrieving revision 1.779
diff -u -F^f -r1.779 common.inc
--- includes/common.inc	19 Jul 2008 10:38:13 -0000	1.779
+++ includes/common.inc	27 Jul 2008 02:42:05 -0000
@@ -3058,8 +3058,10 @@ function drupal_get_schema($table = NULL
       // Invoke hook_schema for all modules.
       foreach (module_implements('schema') as $module) {
         $current = module_invoke($module, 'schema');
-        _drupal_initialize_schema($module, $current);
-        $schema = array_merge($schema, $current);
+        if (is_array($current)) {
+          _drupal_initialize_schema($module, $current);
+          $schema = array_merge($schema, $current);
+        }
       }
 
       drupal_alter('schema', $schema);