ShareThis plugin on WordPress MU - default in all blogs

I have one instance of Wordpress Multiuser and need ShareThis plugin to be automatically activated in all new created blogs.

I've seen a post:

Plugins placed in wp-content/mu-plugins are automatically enabled for all blogs in the system. They cannot be turned off by the users.

When putting the plugin files into root blog (/plugins/ folder), the plugin is functional, but when putting it into /mu-plugins , the plugin is not working.

What else do i need to do to make it开发者_运维百科 work?

Plugins put in /mu-plugins cannot be in folders.
/mu-plugins can only contain plugin files like what-ever-plugin.php.

The mu-plugins directory will not read plugins in a subfolder, so your ShareThis plugin must be modified to individual file to work.

Any plugin files in a subfolder will be ignored unless included in the primary plugin file.