Posted - May 30 2017 : 22:36:34 The best strategy for this kind of errors is to delete portions of the file until you single out the part that causes the issue.
In your case this was simple, nodes N11 and N12 are coincident:
N12 x=15.0 y=-2.5 z=0 N13 x=15.0 y=-2.5 z=0
This of course is not allowed, but unfortunately is not easy to catch (check if any node is coincident with any other would in principle require N^2 operations; with special algorithms you can lower the complexity, but this is not the goal of FastHenry, and in some cases you may even want coincident notes for your convenience, think about ground planes for instance).
