The HTML 5 Video Player Widget is still available, I think you are running into an intermittent issue a couple others reported.
In Widget Browser, try clearing the Cache by clicking the "Options" button in top right and then the "Clear Cache" button.
Then go to 'Adobe Exchange" and click on the "HTML 5 Video PLayer" widget again.
If it still displays an error ignore it.
Hit Add to My Widgets and try it out.
Let us know if that doesn't fix the problem. I think the download file type may not be set correctly looking into fixing that on the server.
I did try clearing the cache. It is not an intermittent problem. Try deleting the widget or downloading from a PC that doesn't have it already. If it displays an error, the Add to My Widgets is not enabled. That is why I submitted the post.
Now about that download file type ...
I am having the same problem. Error downloading... EOF. I tried clearing my cache but it did not work.
I gave up on a straight HTML5 version. I believe the company that made it stopped supporting it. Adobe refuses to acknowledge this. I ended up creating my own version of HTML5 for offline only using Good Reader's browser, which is incredibly flexible.
My iDevice version simply links to the file and lets the QuickTime player handle the streaming and playing with a "Done" button to return to the interface.
Everything else uses a Flash player for me.
You can try DMXzone HTML5 Video Player it is fully crossbrowser compatible with flash fall back.
It supports even playlists and runs great on iPad and iPhone as well even IE6.
can anyone define me the ablut HTML5 and what is the difference between HTML5 v HTML4
HTML5 includes a tag that allows you to play and control video. It is Apple's dream that all website developers use HTML5 and abandon the Adobe Flash plug-in.