Index: wp-admin/includes/post.php
===================================================================
--- wp-admin/includes/post.php	(revision 22269)
+++ wp-admin/includes/post.php	(working copy)
@@ -1349,7 +1349,7 @@
 	}
 
 	// If a new front page was meant to be created, go forth and create it.
-	if ( 'new' == $_POST['page_on_front'] ) {
+	if ( ! isset( $_POST['page_on_front'] ) || 'new' == $_POST['page_on_front'] ) {
 
 		// If the user can't create pages, revert.
 		if ( ! current_user_can( 'create_posts', 'page' ) ) {