Thanks! Glad you like it. The iPad app is coming soon, but in the meantime the site should work on your iPad without a problem. Mixergy and TED will definitely be coming soon to the list of supported sites.
As for the error, you might've caught us while we were frantically rebooting. :) But I'll check it out.
I assume you already know about http://embed.ly but are concerned about security, like embedding unknown/untrusted html on your site?
I find your idea great and I have built something similar my self. I focused mostly on the interface and the fact that many times when watching a video you want to be able to switch between videos and make them fullscreen without interrupting their download. For example, when you have a long video on youtube that is split into many parts.
Playlists and ratings for videos is also quite useful in my opinion.
If you want some ideas check it out: http://lideo.me - you don't have to register/signup to start using it. You can do that later.
As for the error, you might've caught us while we were frantically rebooting. :) But I'll check it out.