That's scarily similar to an experience I had in a CS2 course
my freshman year. I didn't have the money for a commercial X-Windows server or the courage to install Linux on my desktop. So I was forced to work through a Putty window with no syntax highlighting, and a comment block killed the entire last half of my main program.
Luckily a friend spotted it after a few hours, but I was seriously contemplating switching my major while trying to figure that out.