When trying to use the Way Back Machine - http://web.archive.org/ - on all these sites, be aware that the owner of the website can contact them and have pages that were in the archive removed.
That is why no one will be able to find the Mrs Obama speech at the Rainbow/Push conference in July of 2004 on the net. Gives a whole new meaning to the term “white washed”, eh? Maybe this whole dust up needs to be labeled, “Whiteywashedgate”!
I have been browsing the archive, and these videos are/were sold through the “Akiba Bookstore”. This store is accessed from a link on the church homepage. What’s interesting is that around November 2006, the archived bookstore page completely disappears. Prior to that, it is there (which is where the posted list came from).
From what you say, it appears that someone wishing to protect Obama got the archive to pull down all versions of the bookstore page after November 2006.
It is possible that that a video from 2004 might not have been posted on the site immediately, it may not have appeared there until a later time, which would explain why only the later bookstore pages were eliminated.