That is because the script, by default, uses the first 4. You are meant to go and find switches/variables you are NOT using yet, name them so it's clear they're being used by the script, and then go and edit the script to tell it which switches/variables to use.
What's happening is that because you haven't told the script to use new ones, it's using ones that are already used by other events in your game, and they're going to conflict.
So what you need to do is NOW look at the script, see what switches and variables it uses, go and find the same number of switches and variables that you haven't yet used for your game (this, of course, requires that you put a name against them when you DO use them), name them so you don't accidentally use them later for something different, and go and change the switch and variable ids in the script to the ones you've allocated.