Stirrup Rebar Warning - The multiplicities of other interior knots must be at most degree -2

[Jonathan.Olesen]

This is most likely related, read and understand and you should be able to modify your graph to work.

Dynamo script nods problem

Are your nurbscurves completely straight? Couldn’t tell from the pics… If so extract the start and endpoint and create a new line out of them and feed that into the structural framing node.