Ah, so it’s an encoding error. Here’s the explanation as noted by Stackoverflow:
Codepage 720 is Arabic characters used by MS-DOS back in the day, and seems Ruby do not have a translation table for it.
So it’s all related to your operating system’s language settings. I will ask the NREL developers about this to see if they have a suggestion. In the meantime, it might be worth trying some of the things that have solved encoding issues that others have had on their machines. In particular, I think it might be worth trying out this solution that worked for @seghier 