It turns out I am both much smarter than I give myself credit for, and much dumber!

When I looked at the solutions that were provided here, they included pretty much the things I'd already tried. Further more, when I tried to implement them I had no success - until I looked at the return code in the 'die' statement I added to my write() commands. At that point I suddenly realized that I had my close() statement _inside_ my outer loop!

Moving this statement to where it should be has cleared up all (I wish) my problems, and all is now right with the world - except for the existence of mornings, a problem for which I see no possible solutions.