Linedef Executor 404 "block enemies" flag

[blm768]

I'm trying to set up an area with rising and falling water. I'm using Linedef Executor 404 to raise the water. From what I've read, if I set the "block enemies" flag and set the front X texture offset to the tag of another linedef executor, it will run that executor after the ceiling finishes rising. However, I can't get it to execute. I've tried pointing it at the executor's trigger linedef and at the executor linedef itself, but I haven't had any luck. Is there something I'm missing with my setup?

Edit: Never mind; I've just switched to a gargoyle box.