Infopath xqueru no working

This happens a lot in Infopath, XML that has different namespaces. or funnier, the namespace changes... You need code that can work out is namespace programmatically.

XPathNavigator root = MainDataSource.CreateNavigator();
string fieldValue = root.SelectSingleNode("//*[local-name()='field1']").Value;


http://www.bizsupportonline.net/blog/2009/01/specify-namespaces-use-xpath-queries-infopath/