Hi,
Please change the file /wp-content/plugins/wp-retina-2x/core.php, line 20 from
include('ajax.php' );
to
include( __DIR__.'/ajax.php' );
The include instruction is relative to the first calling script (often index.php). In our case, the ajax.php is not in the same directory, so PHP looks through all the directories mentioned in the php directive include_path, and found it in /usr/share/phpMyAdmin. But the ajax.php from PhpMyAdmin could not load its dependencies correctly at this point, so a fatal error occurs.
Other users do not meet this error because include is not require : PHP goes on when it do not found the file….
