Users cannot get past login page. Website returns an invalid email/password message.

[eluser]Narf[/eluser]
In CodeIgniter's next version, valid_email() will use PHP's filter_var() function to determine if the email is valid or not, so that (possible) issue is already fixed.

A tip for posting code in the future - put the code inside between the [code][/code] tags, so that it looks better and not need manual alignment and/or escaping. You may also want to use gist.github.com for longer batches of code.