'Getting Started with Visualforce' Trailhead - link "Webinar: Intro to Visualforce", video not available

Hi all,
I'm working on the Visualforce Basics module of Trailhead, first unit 'Getting Started with Visualforce'
There's a link near the top of the page, under Introduction to Visualforce: View this webinar recording to get an overview of Visualforce.
https://developer.salesforce.com/page/Webinar:_Intro_to_Visualforce_(2012-Nov)
However, when I try to click on the webinar video it says "An error occurred. Please try again later."
I also clicked on the Recorded Webinar link on that page, which takes me to https://www.youtube.com/watch?v=wo74xdvtvUE - but it says the video is unavailable.
Could someone look into it to get the link back up and running?
Thanks!