MARK,
I KNOW, IT HAS BEEN A WHILE. I RECENTLY CLEANED A CARPET AND APPARENTLY MY GLIDDER GOT SO HOT THAT IT MELTED THE CARPET AND MADE A BLACK SPOT. I HAVE NEVER DONE THIS BEFORE. IS IT POSSIBLE THAT THE CARPET IS VERY CHEAPLY MADE? I THOUGHT THE CARPET WAS WET FROM MY SPRAY, SO HOW COULD THIS HAVE HAPPENED? ANY SUGGESTIONS OR ADVICE? THANKS MARK.

That's a new one on me, Charlie. I've never heard of that happening, in the history of OP-dom. Unless you kept the machine in the same spot for a very long time, instead of continuing to keep it in motion, I can't see how the heat could build up to this degree.
I'm really at a loss for words here.

I'll second that Mark..
Olefin will melt from friction,but this sounds wacky.
There has to be a preexisting condition of some kind. Did the machine bog down at all,put off an odor or something??