Thanks Atsushi.
> > args.AddParam("qload", "", "form/question[@id='1.1']");
>
> Here you pass a string (not a node-set) as the overriden parameter,
Changed to:-
XPathNodeIterator iterator =
doc.CreateNavigator().Select("form/question[@id='1.1']");
args.AddParam("qload", "", iterator);
Cheers,
Mark