Digging deeper the piece of code with problem is: <script type="text/javascript"> $(function(){$('#aa742f457fb822aa7e54d9 .dropzone').filedropbox({ url: 'ajax.php/form/upload/attach', link: $('#aa742f457fb822aa7e54d9').find('a.manual'), paramname: 'upload', fallback_id: 'file-aa742f457fb822aa7e54d9', allowedfileextensions: , allowedfiletypes: , maxfiles: 20, maxfilesize: 0,25, name: 'attach', files: });}); </script>Notice the line: maxfilesize: 0,25,The syntax is wrong.