I see the same issue.
In my apache error log, I see the following error:
PHP Fatal error: Class 'WPCF7_Integration' not found in /var/www/blog/wp-content/plugins/contact-form-7/admin/admin.php on line 31
Thanks
I solved this by going from true to false on the wp-activate.php page:
define( ‘WP_INSTALLING’, false );
No dice I’m afraid. Still broken for me with the same error although with Nginx logs and not apache.
Reinstalling the new version gives me the following:
2015/06/07 19:39:08 [error] 4478#0: *1620 FastCGI sent in stderr: "PHP message: PHP Warning: require_once(/usr/share/nginx/www/wordpress/wp-content/plugins/contact-form-7/admin/admin-functions.php): failed to open stream: No such file or directory in /usr/share/nginx/www/wordpress/wp-content/plugins/contact-form-7/admin/admin.php on line 3
It’s weird because if you look at line 3 of the admin.php file, the includes subdirectory is disappearing:
require_once WPCF7_PLUGIN_DIR . '/admin/includes/admin-functions.php';
Please note that the script is looking for /admin/admin-functions.php and not /admin/includes/admin-functions.php
edit: I’ve gone back to 4.1.2.