I didn't try every single one. However, from what i could tell it appears that the episodes were available at the time the show aired, which basically means they are all dead :/
I was going to a add a link for the Kelly Clarkson episode, but decided to wait.
I'd love to find the British version online somewhere.
I would assume that NBC removed all of their old episode links once the show was picked up by TLC.
We can only speculate as to how long TLC will keep the new episodes online, but I see no harm in including the links as long as they're active.