diff --git a/afg_edit_galleries.php b/afg_edit_galleries.php
index 61571b9..cde145d 100644
--- a/afg_edit_galleries.php
+++ b/afg_edit_galleries.php
@@ -7,7 +7,7 @@
     global $default_gallery_id;
     global $warning;
 
-    if ($_POST['afg_per_page_check']) $_POST['afg_per_page'] = '';
+    if (isset($_POST['afg_per_page_check']) && $_POST['afg_per_page_check']) $_POST['afg_per_page'] = '';
     else {
         if (!(ctype_digit($_POST['afg_per_page']) && (int)$_POST['afg_per_page'])) {
             $_POST['afg_per_page'] = '';