It could be a number of small things:
The common issue if you're running locally is that your Eloqua tracking scripts are either missing or not loading. In the tracking scripts you will likely see the following:
s.src = '//img.en25.com/i/elqCfg.min.js';
Online this is fine because the http/https piece is populated automatically but locally this doesn't happen and it will break. If your code is set up like above you can hard code the http part of the source in for now.
Other issues could include the lookup scripts running prior to page load or simply a misnamed field id.