Hi,
i might be wrong but are you sure your 'nodes' definition is pointing to the repeating table itself?
var nodes = XDocument.GetDOM("Retirement Core Activities").selectNodes("/ns1:myFields/ns1:dataFields/ns1:Retirement_Core_Activities");
in the codes it write it's more like..
var nodes2=XDocument.GetDOM("list_machines").selectNodes("/dfs:myFields/dfs:dataFields/ns2:Landesk_listResponse/ns2:Landesk_listResult/NewDataSet/Table")
have a look at the screenshot of my secondary datasource at url below
http://www.infopathdev.com/forums/p/7371/26922.aspx#26922
(or search for "scarse information on passing parameter to a secondary datasource" in the forums)
my secondary datasource is based on a table returned (Landesk_listResponse) as a result (Landesk_listResult) of a query.
That's not what i can see in your code.