It looks like stage fright to me, while a powerhouse director, he probably doesn't get up in front of a crowd like that all too often.
It's embarrasing when it happens, it's happened to me for sure, back in the old uni days.

I have no doubt that the Teleprompter crapped out, leading to the freak out.

I'm sure he'll recover.
It also feels to me that Samsung might have been stretching when they asked him to discuss how their new curved screen would make the viewing of his movies that much better...

for me, bul$$itting a tech crowd about something like that would be a really hard and scary thing to do, but I could talk to them about Transformers or drums or structural mechanics for most of the day because I could be confident that I know my material and would be able to answer most questions or criticisms.