Index: wp-includes/class-wp-xmlrpc-server.php
===================================================================
--- wp-includes/class-wp-xmlrpc-server.php	(revision 37961)
+++ wp-includes/class-wp-xmlrpc-server.php	(working copy)
@@ -5995,7 +5995,7 @@
 			return new IXR_Error( 404, __( 'Invalid post ID.' ) );
 
 		if ( !current_user_can( 'edit_post', $post_ID ) )
-			return new IXR_Error( 401, __( 'Sorry, you can not edit this post.' ) );
+			return new IXR_Error( 401, __( 'Sorry, you are not allowed to edit this post.' ) );
 
 		/** This action is documented in wp-includes/class-wp-xmlrpc-server.php */
 		do_action( 'xmlrpc_call', 'mt.getPostCategories' );