diff --git a/input_formats.module b/input_formats.module
index 36b7bbb..355a8fd 100644
--- a/input_formats.module
+++ b/input_formats.module
@@ -204,8 +204,12 @@ function input_formats_schema_alter(&$schema) {
   );
   $schema['filter_formats']['fields']['format']['no export'] = TRUE;
 
-  $schema['filter_formats']['fields']['settings']['export callback'] = 'input_formats_export_settings';
-  $schema['filter_formats']['fields']['filters']['export callback'] = 'input_formats_export_filters';
+  if (isset($schema['filter_formats']['fields']['settings'])) {
+    $schema['filter_formats']['fields']['settings']['export callback'] = 'input_formats_export_settings';
+  }
+  if (isset($schema['filter_formats']['fields']['filters'])) {
+    $schema['filter_formats']['fields']['filters']['export callback'] = 'input_formats_export_filters';
+  }
 }
 
 /**