A little rooftop problem

[Matthieu]

Hello,

I am beginning with VTK, and I am trying to visualize a rooftop. It's
actually a broiled down version of my problem, but it will do for now.
The data file is attached.
I run a program to visualize it, and it crashes, dumping core and all
that. The first error VTK finds is something like
vtkUnstructuredGridReader.... Unrecognized keywords: scalars.
I run the same program on the blow.vtk data set, and it works fine,
so the program is probably fine

I would like to know what is wrong with my data file.

I gladly welcome any suggestion.
Thank you,

Matthieu
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# vtk DataFile Version 1.0
roof
ASCII

DATASET UNSTRUCTURED_GRID
POINTS 5 float
 0.0 0.0 0.0
 1.0 0.0 0.0
 0.5 0.5 1.0
 1.0 1.0 0.0
 0.0 1.0 0.0

CELLS 4 16
 3 1 2 3
 3 2 4 3
 3 4 5 3
 3 5 1 3

CELL_TYPES 4
 5
 5
 5
 5

SCALARS thickness8 float
LOOKUP_TABLE default
 0.0
 0.0
 1.0
 0.0
 0.0