Index: wp-admin/plugin-editor.php
===================================================================
--- wp-admin/plugin-editor.php	(revision 19670)
+++ wp-admin/plugin-editor.php	(working copy)
@@ -28,7 +28,7 @@
 	wp_die( __('There are no plugins installed on this site.') );
 
 if ( isset($_REQUEST['file']) )
-	$plugin = stripslashes($_REQUEST['file']);
+	$plugin = stripslashes($_REQUEST['plugin']);
 
 if ( empty($plugin) ) {
 	$plugin = array_keys($plugins);