Question

protected void btnCreateList_Click(object sender, EventArgs e)
{
    SPWeb currentWeb = SPContext.Current.Web;

    Guid webId = currentWeb.ID;

    Guid siteId = currentWeb.Site.ID;
    Response.Write(siteId);

    SPSecurity.RunWithElevatedPrivileges(delegate()
    {
        using (SPSite site = new SPSite(siteId))
        {
            using (SPWeb web = site.OpenWeb(webId))
            {
                site.AllowUnsafeUpdates = true;
                Response.Write("configured successfully");



            }
        }
    });



}

Answer 1

You are probably running the code outside the SharePoint, or before the SPContext is initialized (HTTP handler, for example).