Access Ajax controls in UserControl (ascx) code behind inside MasterPage using C# in ASP.Net

protected void btnSave_Click(object sender, EventArgs e) 
{
    Page GGG =this.Page.Parent.FindControl("GeneratePackage") as Page;
    var name = (GGG.FindControl("tbcontainer") as TabContainer);
    name.ActiveTabIndex = 1;
}

but the it is not access...Can anyone help me to figure out the problem..

Thanks in advance

Santosh