First of all, if you have two separate blocks of code you want to post, in this case a script and a data file, please use two separate code blocks.

Meshing it all into a single file makes it much harder for me to debug this thing. Maybe for YAML data is misformatted? The line numbers in the error message don't match up with the code you posted.

You don't use strict; use warnings;.

You essentially don't check for errors when reading the data file.

Other than that, at least on my computer it works, as long as a (more or less) correctly formatted input file is provided.