Child-theme breaks site

Question

So, I have a child-theme with nothing but the required CSS file in it. Once I activated this child-theme my entire site is down. I end up with 2 questions:

1. How can activating a child-theme with nothing but a CSS in it break my site?
2. How can I revert to my original theme?

These are the errors the site gives me:

Warning: require_once(/wp-content/themes/interio_child/admin/options-framework.php) [function.require-once]: failed to open stream: No such file or directory in /wp-content/themes/interio/functions.php on line 54

Fatal error: require_once() [function.require]: Failed opening required '/wp-content/themes/interio_child/admin/options-framework.php' (include_path='.:/usr/lib/php:/usr/local/lib/php') in /wp-content/themes/interio/functions.php on line 54

Answer 1

Your parent theme is probably broken. I guess it is using code like this:

require_once get_stylesheet_directory() . '/admin/options-framework.php';

So it will search in the child theme for files that are present in the parent theme only. It should use get_template_directory() instead.

Answer 2

@toscho is correct that poor coding in the parent theme has broken your site.

As for your second question, how to revert to your previous theme, if you login to your site via FTP (or SFTP, SSH, etc) and delete or rename the child theme folder, WordPress will detect that this theme no longer exists and revert to the default theme. Then you should be able to visit your themes dashboard page and switch to a theme of your liking.