Sharepoint SPWeb rename - Exception SPException - The security validation for this page is invalid

SharePoint2007securityValidation.cs

//1) Set SPWeb.AllowUnsafeUpdates = true
//2) You may need to validate the FormDigest with ValidateFormDigest

SPSecurity.RunWithElevatedPrivileges(() =>
{
    using (SPWeb thisWeb = site.OpenWeb(webUrl))
    {  
        try
        {
            thisWeb.AllowUnsafeUpdates = true;

            if (!thisWeb.ValidateFormDigest())
                throw new InvalidOperationException("Form Digest not valid");

            thisWeb.Title = newName;
            thisWeb.Update();
        }
        finally
        {
            if(thisWeb != null)
                thisWeb.AllowUnsafeUpdates = false;
        }
    }
});