diff --git a/wp-includes/class-wp-xmlrpc-server.php b/wp-includes/class-wp-xmlrpc-server.php
index dc22bfa89..ab616f6c8 100644
--- a/wp-includes/class-wp-xmlrpc-server.php
+++ b/wp-includes/class-wp-xmlrpc-server.php
@@ -1473,7 +1473,7 @@ class wp_xmlrpc_server extends IXR_Server {
 		do_action( 'xmlrpc_call', 'wp.newTerm' );
 
 		if ( ! taxonomy_exists( $content_struct['taxonomy'] ) )
-			return new IXR_Error( 403, __( 'Invalid taxonomy.' ) );
+			return new IXR_Error( 403, __( 'Invalid taxonomy' ) );
 
 		$taxonomy = get_taxonomy( $content_struct['taxonomy'] );
 
@@ -1561,7 +1561,7 @@ class wp_xmlrpc_server extends IXR_Server {
 		do_action( 'xmlrpc_call', 'wp.editTerm' );
 
 		if ( ! taxonomy_exists( $content_struct['taxonomy'] ) )
-			return new IXR_Error( 403, __( 'Invalid taxonomy.' ) );
+			return new IXR_Error( 403, __( 'Invalid taxonomy' ) );
 
 		$taxonomy = get_taxonomy( $content_struct['taxonomy'] );
 
@@ -1653,7 +1653,7 @@ class wp_xmlrpc_server extends IXR_Server {
 		do_action( 'xmlrpc_call', 'wp.deleteTerm' );
 
 		if ( ! taxonomy_exists( $taxonomy ) )
-			return new IXR_Error( 403, __( 'Invalid taxonomy.' ) );
+			return new IXR_Error( 403, __( 'Invalid taxonomy' ) );
 
 		$taxonomy = get_taxonomy( $taxonomy );
 
@@ -1720,7 +1720,7 @@ class wp_xmlrpc_server extends IXR_Server {
 		do_action( 'xmlrpc_call', 'wp.getTerm' );
 
 		if ( ! taxonomy_exists( $taxonomy ) )
-			return new IXR_Error( 403, __( 'Invalid taxonomy.' ) );
+			return new IXR_Error( 403, __( 'Invalid taxonomy' ) );
 
 		$taxonomy = get_taxonomy( $taxonomy );
 
@@ -1773,7 +1773,7 @@ class wp_xmlrpc_server extends IXR_Server {
 		do_action( 'xmlrpc_call', 'wp.getTerms' );
 
 		if ( ! taxonomy_exists( $taxonomy ) )
-			return new IXR_Error( 403, __( 'Invalid taxonomy.' ) );
+			return new IXR_Error( 403, __( 'Invalid taxonomy' ) );
 
 		$taxonomy = get_taxonomy( $taxonomy );
 
@@ -1852,7 +1852,7 @@ class wp_xmlrpc_server extends IXR_Server {
 		do_action( 'xmlrpc_call', 'wp.getTaxonomy' );
 
 		if ( ! taxonomy_exists( $taxonomy ) )
-			return new IXR_Error( 403, __( 'Invalid taxonomy.' ) );
+			return new IXR_Error( 403, __( 'Invalid taxonomy' ) );
 
 		$taxonomy = get_taxonomy( $taxonomy );
 
@@ -2950,7 +2950,7 @@ class wp_xmlrpc_server extends IXR_Server {
 			return $this->error;
 
 		if ( !current_user_can( 'upload_files' ) )
-			return new IXR_Error( 403, __( 'You are not allowed to upload files to this site.' ) );
+			return new IXR_Error( 403, __( 'You do not have permission to upload files.' ) );
 
 		do_action('xmlrpc_call', 'wp.getMediaItem');
 
@@ -2995,7 +2995,7 @@ class wp_xmlrpc_server extends IXR_Server {
 			return $this->error;
 
 		if ( !current_user_can( 'upload_files' ) )
-			return new IXR_Error( 401, __( 'Sorry, you cannot upload files.' ) );
+			return new IXR_Error( 401, __( 'You do not have permission to upload files.' ) );
 
 		do_action('xmlrpc_call', 'wp.getMediaLibrary');
 
@@ -3104,7 +3104,7 @@ class wp_xmlrpc_server extends IXR_Server {
 		do_action( 'xmlrpc_call', 'wp.getPostType' );
 
 		if( ! post_type_exists( $post_type_name ) )
-			return new IXR_Error( 403, __( 'Invalid post type.' ) );
+			return new IXR_Error( 403, __( 'Invalid post type' ) );
 
 		$post_type = get_post_type_object( $post_type_name );
 
@@ -3679,7 +3679,7 @@ class wp_xmlrpc_server extends IXR_Server {
 				$post_type = 'post';
 			} else {
 				// No other post_type values are allowed here
-				return new IXR_Error( 401, __( 'Invalid post type.' ) );
+				return new IXR_Error( 401, __( 'Invalid post type' ) );
 			}
 		} else {
 			if ( $publish )
@@ -3735,7 +3735,7 @@ class wp_xmlrpc_server extends IXR_Server {
 						return(new IXR_Error(401, __('You are not allowed to create pages as this user')));
 					break;
 				default:
-					return(new IXR_Error(401, __('Invalid post type.')));
+					return(new IXR_Error(401, __('Invalid post type')));
 					break;
 			}
 			$author = get_userdata( $content_struct['wp_author_id'] );
@@ -3987,7 +3987,7 @@ class wp_xmlrpc_server extends IXR_Server {
 
 		// Use wp.editPost to edit post types other than post and page.
 		if ( ! in_array( $postdata[ 'post_type' ], array( 'post', 'page' ) ) )
-			return new IXR_Error( 401, __( 'Invalid post type.' ) );
+			return new IXR_Error( 401, __( 'Invalid post type' ) );
 
 		// Thwart attempt to change the post type.
 		if ( ! empty( $content_struct[ 'post_type' ] ) && ( $content_struct['post_type'] != $postdata[ 'post_type' ] ) )
@@ -4039,7 +4039,7 @@ class wp_xmlrpc_server extends IXR_Server {
 						return(new IXR_Error(401, __('You are not allowed to change the page author as this user.')));
 					break;
 				default:
-					return(new IXR_Error(401, __('Invalid post type.')));
+					return(new IXR_Error(401, __('Invalid post type')));
 					break;
 			}
 			$post_author = $content_struct['wp_author_id'];
@@ -4531,7 +4531,7 @@ class wp_xmlrpc_server extends IXR_Server {
 		do_action('xmlrpc_call', 'metaWeblog.newMediaObject');
 
 		if ( !current_user_can('upload_files') ) {
-			$this->error = new IXR_Error(401, __('You are not allowed to upload files to this site.'));
+			$this->error = new IXR_Error( 401, __( 'You do not have permission to upload files.' ) );
 			return $this->error;
 		}
 
diff --git a/wp-includes/taxonomy.php b/wp-includes/taxonomy.php
index bfe516a9b..8ea976ffa 100644
--- a/wp-includes/taxonomy.php
+++ b/wp-includes/taxonomy.php
@@ -502,7 +502,7 @@ function get_objects_in_term( $term_ids, $taxonomies, $args = array() ) {
 
 	foreach ( (array) $taxonomies as $taxonomy ) {
 		if ( ! taxonomy_exists( $taxonomy ) )
-			return new WP_Error( 'invalid_taxonomy', __( 'Invalid Taxonomy' ) );
+			return new WP_Error( 'invalid_taxonomy', __( 'Invalid taxonomy' ) );
 	}
 
 	$defaults = array( 'order' => 'ASC' );
@@ -855,7 +855,7 @@ function &get_term($term, $taxonomy, $output = OBJECT, $filter = 'raw') {
 	}
 
 	if ( ! taxonomy_exists($taxonomy) ) {
-		$error = new WP_Error('invalid_taxonomy', __('Invalid Taxonomy'));
+		$error = new WP_Error('invalid_taxonomy', __('Invalid taxonomy'));
 		return $error;
 	}
 
@@ -984,7 +984,7 @@ function get_term_by($field, $value, $taxonomy, $output = OBJECT, $filter = 'raw
  */
 function get_term_children( $term_id, $taxonomy ) {
 	if ( ! taxonomy_exists($taxonomy) )
-		return new WP_Error('invalid_taxonomy', __('Invalid Taxonomy'));
+		return new WP_Error('invalid_taxonomy', __('Invalid taxonomy'));
 
 	$term_id = intval( $term_id );
 
@@ -1174,7 +1174,7 @@ function &get_terms($taxonomies, $args = '') {
 
 	foreach ( $taxonomies as $taxonomy ) {
 		if ( ! taxonomy_exists($taxonomy) ) {
-			$error = new WP_Error('invalid_taxonomy', __('Invalid Taxonomy'));
+			$error = new WP_Error('invalid_taxonomy', __('Invalid taxonomy'));
 			return $error;
 		}
 	}
@@ -1875,7 +1875,7 @@ function wp_get_object_terms($object_ids, $taxonomies, $args = array()) {
 
 	foreach ( (array) $taxonomies as $taxonomy ) {
 		if ( ! taxonomy_exists($taxonomy) )
-			return new WP_Error('invalid_taxonomy', __('Invalid Taxonomy'));
+			return new WP_Error('invalid_taxonomy', __('Invalid taxonomy'));
 	}
 
 	if ( !is_array($object_ids) )
@@ -2146,7 +2146,7 @@ function wp_set_object_terms($object_id, $terms, $taxonomy, $append = false) {
 	$object_id = (int) $object_id;
 
 	if ( ! taxonomy_exists($taxonomy) )
-		return new WP_Error('invalid_taxonomy', __('Invalid Taxonomy'));
+		return new WP_Error('invalid_taxonomy', __('Invalid taxonomy'));
 
 	if ( !is_array($terms) )
 		$terms = array($terms);