Thanks Igor. As you suggested, I ditched the attempt to store SqlConnection and DataAdapter classes, and created a new insance when I needed them. It works fine now. I am still caching the dataset, because it is relatively small and I think I'd take a bigger hit from loading it every time I need it (which is often). But I'll watch out for this as I scale my app.

Run the code SessionEnd event as well if its a ASP.NET web page. Look where you want to go not where you don't want to crash. Bikers Bible

That's a good idea, thanks. I already built a class that I think matches the XML. Should be simple to serialize an object and compare it to the XML I'm trying to deserialize.

I think I may have answered my own question with a little more web searching. Looks like I should use the Deserialize() method of the XmlSerializer class to convert the XML string into an object type. I'm still a little shaky on OOP, but I can then cast the object into a custom defined type so I can extract the fields I need, right?