custom error page for comments

Hi, I have designed a new theme for my word press blog but I also want to customise errors on the site. Not 404 errors but say for example someone goes to leave a comment and they do not fill in the email address, It currently just goes to a blank page saying:

Error: please fill the required fields (email).

Is there a way to make this more elegant and post the original form page with some HTML changes to highlight the issue?

I have been looking through plugins and searching through the docs here and Google searches but no luck.

Thanks. 🙂