Downloadfehler

//  Downloadbutton.uc.js

(function() {

   if (location != AppConstants.BROWSER_CHROME_URL) return;

    try {

             CustomizableUI.createWidget({
             id: 'Download-button',
             type: 'custom',
             defaultArea: CustomizableUI.AREAS,
             onBuild: function(aDocument) {         
                var toolbaritem = aDocument.createElementNS('http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul','toolbarbutton');
                var props = {
                   id: 'Download-button',
                   class: 'toolbarbutton-1 chromeclass-toolbar-additional',
                   removable: true,
                   label: 'Download Fenster öffnen',
                   tooltiptext: 'Download Fenster öffnen',
                   style: 'list-style-image: url(file:///H:/Icons/downloadbutton.png)',
                   oncommand: "window.open('chrome://browser/content/downloads/contentAreaDownloadsView.xul', 'Downloads', 'chrome,resizable=yes,width=600,height=750,left=1220,top=100');"
                };          
                for (var p in props)
                   toolbaritem.setAttribute(p, props[p]);            
               ownload return toolbaritem;
             }      
          });
          CustomizableUI.registerToolbarNode(tb);
        } catch(e) { };
        }) ();