Okay, I waited till my officemate left for the day and then closed the office door. I played one video (Take a Chance) on the MM Channel and then it wouldn't play any more videos, giving me the message:
"The Adobe Flash Player is required for video playback. Get the latest Flash Player."
I tried the Up Front Channel, watched the latest S/mileage video and then tried to play another and got the same message.
Now, this is a new computer, a brand new Mac installed about three weeks ago, so you'd think the geniuses who installed everything on it would have given me the latest Flash Player.
Anyway, so I clicked on the thing to install the latest Flash Player and I get a page that says this:
Thank you. Your download will start immediately and may take a few minutes to complete.
And then nothing...nothing...nothing.
This is why I prefer physical media and a DVD player.

I have a year-old computer at home, a PC, and I have no idea what the result will be when I try it there. I'll report back.