Hi
@Erel,
today (yes, I'm a bit late on this..eheh) I opened up your ETP page to browse on available lessons. I found that a few videos don't load on my PC, quite surely due to some firewall rule I set in the past. Honestly, my hope is that you can say there are differences in how the videos are published so it could happen that a few don't load easily everywhere.
Just to give you a reference, on first row I can open first and third video, while the remaining two show a message offering to download them.
If you need a complete list, just let me know.
UPDATE: setting directly the failing videos' vimeo URLs in the browser they play regularly.