Adding video to the Poster 2 stack

I am using RW 8.9.1, Stacks 4, and Poster2. What I want to do is insert a video player on the main blog page. I have tried the HTML5 stack and the demo of VideoPlayer, but both give me this message when I go to the view mode:
Notice : fread(): read of 8192 bytes failed with errno=21 Is a directory in /Applications/RapidWeaver
(When I add text below the video, the does not appear in the view mode, either.)

Can anyone translate that message for me? What am I failing to do?

This is how I have set the page up:

Thanks in advance!

Which kind of video? YouTube, Vimeo, own mp4… ?

And, as you’ve had preview problems, is this error also appearing on the published website?

Hi Jannis, sorry for more drama!

My own mp4, hosted with the site. I haven’t published it yet because I am adding new pages to my original project, which I plan to swap out when they are ready. But if you think that will help, I can try publishing it without it showing in the navigation.

But if it did work, that means I can’t see my blog pages in edit form?

Oh Lordy. I just removed the video stack and just added text to the Main Content box… and get the same message when I try to view it! So it isn’t the video that’s causing the problem. I guess I need a new topic!

RW has its preview flaws. I suggest adding a new page, don’t show it in the navigation, and publish it.

In addition, Poster comes with an own audio and video player, allowing you to play audio (MP3) and video (MP4) files.

That would probably be easier, to just use yours. I will give that a try and see whether it all comes together.