[RPG] How to run a game of Dread over the Internet

Why does it ruin everything? If the GM caused the fall then re-stack and pre-pull the same as if a player had.

If at any time a player other than the host causes the collapse of the tower, their character is removed from the game.

This implies to me that if the host causes the collapse then nothing much happens, just re-stack and pre-pull the correct number for the number of remaining players.

Page 50 is clearer:

Don't sit near the tower. Nothing happens in the game if you knock it over, but the story will grind to a violent halt. If it does happen, rebuild the tower and ask for some free pre-pulls -- this is the only time besides the beginning of the game when a tower fall does not mean the removal of a character.

Italic emphasis mine.

I haven't played the published scenario in Dread, but I have played my share of original games. This question is somewhat hard to answer, as anyone can make any kind of "mistake", but here are somethings I'd advise you to keep in mind:

1. Kill 'em - If someone knocks it over, don't take it back or try to "soften the blow" people need to die.
2. Watch the pace - I alluded to this in your other Dread question (How do you handle an early death in Dread?), basically your main task as a GM is to have the right number of pulls going on. I've found starting slow and then speeding up later is a good way to build to an exciting, bloody climax
3. Don't try to complicate it - Having a lot of variability in the number of pulls to make or trying to add in other mechanics slows down the flow of the game. The simplicity of the rules is part of what makes it so much fun.
4. Let people willingly fail - If someone wants to not pull and just fail a task, let them. In general a party of people daring each other to go down the scary hallway is one of the great moments of a Dread game.