Hi thebaul,
I have attached your scene file with one more node, the New Node>XPresso>Calculate>Vector2Matrix node. (Please note that the New Node>XPresso>Adapter>Vectors2Matrix is a differnt one!) As the Spline Node allows for a “Tangential” read out, I use this to feed the “Alignment” input of the PSetData node. If you click on that node, you get an option to specify X,Y or Z as your orientation.
There might be a slight chance that you run into an “Euler-Angle” http://en.wikipedia.org/wiki/Euler_angles
If so the set up is more complex of course, sometimes a single “PPosition Follow” might helps to a certain degree, as simple fix.
I have set the XPresso Tag in the Attribute Manger to “Camera Dependent”, to have a better refresh of the scene, you might shut it of for your needs.
I have sorted the XGroup, so the flow of information is streamlined and perhaps helps with more data to come to the scene to keep it working. A typical work that I do to have things clean, which might most of the time not needed.
BTW, as this question was not a problem inside of the tutorial, I ahve moved it to the Cineversity Q&A, so people with a direct problem of the tutorial might not have to read through an extended question.
All the best
Sassi