PressThis 404 Error

Here is the code I have stored for my pressthis:
javascript:var%20d=document,w=window,e=w.getSelection,k=d.getSelection,x=d.selection,s=(e?e():(k)?k():(x?x.createRange().text:0)),f='http://www.hugh-fraser.co.uk/wp-admin/press-this.php',l=d.location,e=encodeURIComponent,g=f+'?u='+e(l.href.replace(/\//g,'\\/'))+'&t='+e(d.title)+'&s='+e(s)+'&v=2';function%20a(){if(!w.open(g,'t','toolbar=0,resizable=0,scrollbars=1,status=1,width=720,height=570')){l.href=g;}}a();void(0);

I have looked in my wp-admin folder on my server and press-this.php is there so I don’t know why I am getting a 404 error.

All help is very much appreciated.
Thank you
Hugh