Try replacing line 2 with: a=load 'sunspotdata.mat';
Additionally, you will notice that there are warning glyphs on the side of your MathScript Node. These mean that you are operating with reduced error checking at edit time and will experience slower run-time performance for the MathScript Node. For more info on resolving this you can right click on the MathScript Node and select help or you can browse here: http://zone.ni.com/reference/en-XX/help/371361G-01/gmath/mathscript_node/#warning
