The problem is Google retired the old version of gmail which the bookmark-let is trying to use. To fix it change the ui=1 to ui=2 in the code.

or you can drag this new link up Gmail this

javascript:(function(){m=’http://mail.google.com/mail/?ui=1&view=cm&fs=1&tf=1&to=&su=’+encodeURIComponent(document.title)+’&body=’+encodeURIComponent(document.location);w=window.open(m,’addwindow’,'status=no,toolbar=no,width=575,height=545,resizable=yes’);setTimeout(function(){w.focus();},%20250);})();