[Luke Pike]

I did exactly what you did and found the same thing. It took me forever to figure out how to add inputs and outputs to a vi. For the error, right-click the unbundle that's set to "Code" and create a control.

Next you have to switch to the front pane, then right-click the icon of the vi and select "Show Connector". You'll see a diagram where the icon was. If you want an input, click on a segment to the left, then click on the control you want, in this case the error in. Now when you use that vi, you'll be able to wire in an error. Hope that helps!