I've finished Skelebot's _t.c file for the time being (although it's not totally complete. I'm working on about 6 bots at once). When I tried it again along with rnd.c, it worked fine.
I have a theory on what might have caused the problem before. It was something I didn't mention previously.
What I was doing was this: I wanted to test out the
interjection_negative string, so I made about half a dozen of Skelebot's comments say that. Maybe there was too much repetition? I don't know if there is a limit on how many times you can reference the same string in the one _t.c file. (However, it was recognising none of the random strings, not just the
interjection_negative string.)
Anyway, it's working properly now and progress will continue.