public override void FeatureActivated(SPFeatureReceiverProperties properties)
    {
        //  SPSite site = properties.Feature.Parent as SPSite;
        SPSite site = new SPSite("http://.../sites/G");
        using (SPWeb oWeb = site.RootWeb)
        {

            //Get the Page Url where Webpart needs to be added.
            string strTargetPage = oWeb.Url + "/SitePages/Home.aspx";
            //  string strTargetPage = "/sites/G/SitePages/Home.aspx";
            string strWebPartName = "ATForm1.webpart";
            Microsoft.SharePoint.WebPartPages.SPLimitedWebPartManager Mgr = oWeb.GetLimitedWebPartManager(strTargetPage, PersonalizationScope.Shared);

            //Get WebPart from the WebPart Gallery
            SPQuery query = new SPQuery();
            query.Query = string.Format("<Where><Eq><FieldRef Name='FileLeafRef'/><Value Type='File'>{0}</Value></Eq></Where>", strWebPartName);
            SPList WebPartGallery = oWeb.GetCatalog(SPListTemplateType.WebPartCatalog);
            SPListItemCollection webparts = WebPartGallery.GetItems(query);

            //Get the XML from the WebPart File
            XmlReader xmlReader = null;
            if (webparts != null || webparts.Count != 0)
            {
                Stream xmlStream = webparts[0].File.OpenBinaryStream();
                StreamReader sReader = new StreamReader(xmlStream);
                StringReader strReader = new StringReader(sReader.ReadToEnd());
                xmlReader = XmlReader.Create(strReader);
            }

            //Add the WebPart to the Page
            if (xmlReader != null)
            {
                string errMsg = "";
                System.Web.UI.WebControls.WebParts.WebPart WP =
                Mgr.ImportWebPart(xmlReader, out errMsg);
                WP.Title = "WebPart Added From Gallery";
                Mgr.AddWebPart(WP, "Left", 1);
            }
        }
    }