There was a problem with windows not finding the path to the toolboxes. I was able to get it working on my machine by changing the first line of code (commented out) to the second. Also fixed ...
lookup-table.txt is required to specify the correct GABC notation for any neum that the GRG file contains. For example, lookup-table.txt could be as follows: 1 s ; 2 s , 3 s :: 12 n ji 19 n ef 24 n i ...