Thank you for your offer. Obstinance having gotten the better of me, I just deleted the en_us files and reinstalled them. When I edited the moodle.php again, I was very careful. The problem still persisted. Then, I copied the moodle.php into the en folder and - voila! it was fixed.
Thanks to all for your help. What a great community. I hope to become proficient enough to be of assistance in my turn some day. *tips hat*