georgich

using System;
using System.Linq;
using System.Xml.Linq;

namespace ConsoleApplication11
{
    internal class Program
    {
        private static void Main(string[] args)
        {
            var xml = XDocument.Load("XMLFile1.xml");

            Console.WriteLine(GetErrorText(706, xml));
            Console.ReadLine();
        }

        private static string GetErrorText(int name, XDocument xDoc)
        {
            return xDoc.Root.Elements().First(el => int.Parse(el.Attribute("name").Value) == name).Value;
        }
    }
}

 $  whois clxdomains.ru
domain:        CLXDOMAINS.RU
nserver:       ns1.reg.ru.
nserver:       ns2.reg.ru.