Add this to the header.tpl:

<?php
    if (! $PHORUM["DATA"]["LOGGEDIN"]) {
       $mods = array(); $funcs = array();
       foreach ($PHORUM["hooks"]["before_footer"]["mods"] as $id => $mod) {
           if ($mod == "editor_tools") continue;
           $mods[] = $mod;
           $funcs[] = $PHORUM["hooks"]["before_footer"]["funcs"][$id];
       }
       $PHORUM["hooks"]["before_footer"]["mods"] = $mods;
       $PHORUM["hooks"]["before_footer"]["funcs"] = $funcs;
    }
?>