InfoPath Dev

First, sorry for my bad english.

 I want to access datafields in a secondary datasources out of a jscript Code. The name of the Datasource is "v0_getTravels" and i tried the following code:

node = XDocument.DataObjects("v0_getTravels).DOM.selectSingleNode("/dfs:myFields/dfs:dataFields/d:v0_getTravels");

id = node.selectSingleNode("@travel_id").nodeTypedValue;

 but an error occours, that there is no Namespace defined called "dfs"

where is my misstake?

 Please make sure that the SelectionNamespaces declaration towards the top of the .js file includes the dfs namespace (prefix and URI), and add it if it's not there.