Well, it's 6 months since this post was posted, and I am here to say that I'm giving up! I'm so tired of going through the whole upload process, and then ending up with a video that doesn't play!
Never going back there until there's an announcement that they've worked out the bugs!
Me either ... I wonder what the issue really is here...
I decided that if I want to post a video, I'm gonna upload it to YT, then drag it into my post here.