Hello TK,
Fortunately I have fixed the problems. It turned out the sign-up form was not linked to the plug-in at all.
But I have one more question, how do I make the submit button on my homepage as pretty as the ones I set up on the official mail chimp site?
http://www.chicago-project.org: go to the side bar and see the first sign-up box (set up from plug-in)
http://chicagobureau.us7.list-manage.com/subscribe?u=5ad83dbb72cd23b671ac284a1&id=ce95ba0ede: (set up on mailchimp.com)
*The site is still under construction so please do not share.