The most helpful error message ever

System

Interwoven, how helpful is this error message supposed to be (see attached GIF)?

I''m hoping to get some meaningful context to what I'm doing wrong, although I have a guess...

I edit a DCR and hit FINISH. This action starts a workflow which deploys and then sends me an email asking me if I want to add a landing page to my workflow? For this, I am using the addnewformtotask CCI URL. Everything works nicely so far, I save the file and then hit FINISH to give me the <sarcasm>lovely and descriptive</sarcasm> error message you see attached to this message.

Two possibilities: I'm attempting to attach it to a task that is no longer valid. This could be the problem although I have no visual indication of such -- okay, okay, I'll get off it. Otherwise, I'm not providing a DONE PAGE parameter but I understand that this is optional.

So, what's the deal?