structures of the vanilla world don't work

[dimactek96]

If using
"Quick-Start Guide (No-World-Manager)
Step 1: Install Iris to a server (Server must be off, and do not use plugins such as Plugman or Hotplug)
Step 2: Add the following to the bottom of the bukkit.yml file:
worlds:
world:
generator: Iris
Step 3: Start the server. You will likely see a lot of this: Couldn't find Dimension: Overworld. Ignore this.
Step 4: Wait. Iris will now generate a world for you. This should only happen on the first run, it will load much faster after. If this takes longer than 5 minutes feel free to restart the server, it should fix any hitches it had. This should not occur."
If you use this, then there will be no vanilla structures.