functions_display.php defines the following template variable for the forumrow block which fails to obtain the appropriate language value from the $user->lang array. The returned value is simply the array key. Bantu suggested removing it as FORUM_FOLDER_IMG_ALT performs the same function correctly.

'L_FORUM_FOLDER_ALT'	=> $folder_alt,

viewtopic.php defines the following template variable which uses the SEARCH_USER_POSTS lang key as alt text. The key is defined in language/en/memberlist.php, so the actual language value is never returned.

'SEARCH_IMG' 		=> $user->img('icon_user_search', 'SEARCH_USER_POSTS'),