I finally found it:
http://www.funtrivia.com/crossword/play.cfm?gid=2246

"A Countdown from Nine to Zero" in the General category. I've tried it on both my iPad and desktop.

I did crossword “Music Box 7” and was pretty sure it was correct, but it didn’t clear the screen. I looked it over very carefully for about a half an hour and finally concluded I must have made a mistake, so I gave up and pressed the “Easy Mode” button. Nothing changed. I toggled back and forth between Easy and Hard and there was no change. I left it on my screen if there’s any way someone can look at it.

http://www.funtrivia.com/crossword/play.cfm?gid=2711

I played that crossword and it immediately whisked me away, no problem.

Loaded the grid a second time, entered a bunch of Es and activated easy, got a nice mix of green and red too. All as it should be.

Well, thanks. I guess I’ll just abandon it.