For a long time the video links on https://commons.wikimedia.org/wiki/Wikimania_2005_Presentations have been broken, pointing to some abandoned server in Amsterdam. It looks like the videos were never uploaded to Commons, perhaps due to file size limits or other limitations in place at the time.
I just noticed that the Wayback Machine has copies of most of them: http://web.archive.org/web/20070720024828/http://www.knams.wikimedia.org/wik...
Any takers for getting these up on Commons? I noticed that unfortunately files >100MB seem cut off including the higher quality copies, so unless there's other copies of these around, it'll be hard to recover them. (This may be a limit on archive.org's crawler, or it may be a limit on how much content they serve. I suspect it's the former, but will ping them as well.)
Erik