This is the third time it happened on t.c.m. on demand.I was trying to watch,"The last time I saw Paris.Instead of the movie, I got a dark blank space.This is the umpteenth time that t.c.m does not fix it, also.
Try right-clicking on the black screen. If you get some options for settings like "allow Adobe flash player," try that. I use Firefox and recently I started getting a dark grey screen. When I right-clicked and allowed Adobe flash player, the problem disappeared. I also use Internet Explorer from time to time, and have no problem with that browser.