It appears that on the entire Internet, there is not a single transcript for Legend of the BoneKnapper Dragon or for Gift of the Night Fury. Even more unfortunate, the original copies of the scripts haven't even been leaked (yet)!
We thought this was sad.
So we wrote them ourselves. You can read them here:
Legend of the BoneKnapper Dragon
Gift of the Night Fury
How to Train Your Dragon (official copy, with bonus material!)
And, once the TV show starts, you can look forward to transcripts of every episode as well!