I'm trying to make an item that transports you to another room as soon as you pick it up.

So I set it to run a scrip when you pick it up, and that script also locks the exit. Obviously I picked the Lock exit script, and there are 2 drop-down boxes in it. The first one has Exit or Expression available, so I just keep it as Exit, but the second one is just empty. It's just a thin, somewhat long drop-down box that looks like it should be displaying numbers or something based on the size of the box, but it's just empty.

And the game is expecting me to do something with this box too, because when I try to run the game like this just leaving it alone, it gives me an error. I've seen a couple other scripts have the same exact empty drop-down box and have pretty much been unable to use those scripts.

Any ideas what this means?

As far as I know, that box should list all named exits. You can't lock an exit unless you give it a name.