Likely an out of date interpreter, yeah. Gargoyle's TADS interpreter is well out of date at the moment, although people have been working on that. I suggest QTADS or playing online (there's a link to the online version on the game's page).
That said, Lynnea Glasser got a text encoding error when she played it for Twitch, and I don't know why. The game still worked fine for her. ¯\_(ツ)_/¯