Index: plugin-install.php
===================================================================
--- plugin-install.php	(revision 9859)
+++ plugin-install.php	(working copy)
@@ -771,7 +771,7 @@
 
 	if( $wp_filesystem->exists( $plugins_dir . $filelist[0] ) ) {
 		$wp_filesystem->delete($working_dir, true);
-		return new WP_Error('install_folder_exists', __('Folder allready exists.'), $filelist[0] );
+		return new WP_Error('install_folder_exists', __('Folder already exists.'), $filelist[0] );
 	}
 
 	apply_filters('install_feedback', __('Installing the plugin'));