Introduction to MPI by Aveuh - Standard Error

I’ve been learning MPI little by little with this course, and it is really helpful. But every time I try to run the exercises, I always get a Standard Error message that begins with this statement:
Unexpected end of /proc/mounts line `overlay / overlay…
Although some of the code runs, I don’t always get to see all the statements I wanted to print out, so I think the problem is in the Standard Error.