Answer by Jon Skeet for Building a Google Product Feed in .Net (C#)?

The problem is that you're trying to create an element with a name of rss version="2.0". Instead, you should be creating an element with a name of rss, and setting the version attribute to have a value of 2.0:

xw.WriteStartElement("rss");xw.WriteAttributeString("version", "2.0");

Personally I'd use LINQ to XML instead of XmlWriter to start with, mind you - it's a much nicer API.