Login failed, Function.php need troubleshoot

Hi everyone.
I have edited the function.php 2 days ago. Added only one-line code. And today I encounter problem with login.
I have done a search for function.php in wpInclude, wpAdmin, Theme, however, couldn’t find the code last added.
The last note I remembered was comment has added. And this comment show at the login page on the top left corner, http://cyperwin.com/wp-login.php
Once I login, same message appear at same corner on totally blank page.
Pls help.

Thank you,
Edwin