What's wrong with the rubric?

Last week at our meeting after school with Freshman IZ teachers and administrators, we talked about our (somewhat failed) use of rubrics in the classroom. I haven't understood why the students don't make better use of the rubric as a guide to complete their final product. Kristin said something that shed better light on the topic for me: "They understand that we use it as a grading form, but they don't understand that it's their instructions."
So, how do we bridge this gap for them? Tomorrow we're going to try a "Fakebook" activity in which students will be creating a "Fakebook" page (info, posts, comments) as characters from the Giver and leaders of the Persian and Chinese Empires. We've structured the rubric more like a checklist in hopes of their going step by step through them.
We'll see if this slight change makes a difference! I can't wait to meet with Matt this week and get help!