There is a nasty bug in 1.5.9w that prety much screwed things up.
Please send me an email at info@nodecanvas.com and I will reply to you with the latest version 1.6.
By the way in that version the callback parameter in the ExecuteAction has been removed due to the way action execute now, but I can as well re-add it for standalone, out of NC calls, if you made use of that.
Gavalakis
