To answer #3, you need to make sure to add a ToolkitScriptManager. Without that, no Ajax controls will work. See here:
Display a Simple Popup Calendar[
^]
As far as #2, it probably has to do with your UICulture. Before setting the system date, try changing your Culture and UICulture. You can do that easily by doing:
Thread.CurrentThread.CurrentCulture = new CultureInfo("en-US");
Thread.CurrentThread.CurrentUICulture = new CultureInfo("en-US");
You just need to add
using System.Threading;
using System.Globalization;
As far as #1, I have no idea what you're asking. I assume English is not your first language because it makes no sense in English.