The title for the who's online bit always reads "Users browsing the gallery"... this *should* be "Users browsing the Ads" or whatever is specified in the pp_inc.php language file.
I necessarily would not call a language string preference a bug as thats a bit harse
Basically if a script has a language file equivelant it overrides the pp-inc.php language file so in index.php language file update that language string.