I think the Video thumbnails arent displaying because you haven't got FFMEPG-PHP installed on your server. FFMEPG goes through the video you upload and it then grabs a shot from one of the frames that you specify and that is what is then available to you as a thumbnail.
He's using coda ( http://www.panic.com/coda/ ). A web development IDE for the Mac OS X. From what i have seen, it not really not that great especially from the intellisense side of things but hey that 's just my opinion.... lots of people like it.
One of the best and really powerful, cross-platform, free and open source web dev IDE i would recommend is called Aptana ( http://aptana.com ).. It's got great intellesene and many other awesome features and code development for many other languages (PHP, Ruby on Rails, Python etc) and platforms (Nokia and IPhone) are available as free plugins.
The only downside is that it tends to be heavy on memory so make sure that you have an extra 350MB of RAM. :)