Index exceeds Matrix dimensions

Hi!

I am trying to run this script to calculate different values for an assignment. Ive gotten most of it to work, but it is now stuck on line 162 when i run it, and tells me "index exceeds matrix dimensions". I have tried to compare the two matrixes i am trying to combine, and one of them seems to have a lot of zeros in it. Is there any way to elegantly fix this problem, and get rid of the index error?

The files "stralning" and "temperatur" are the text files that i am getting my data from, just for reference.

Thank you for any help!