Fatal error when trying to acces plugins.

Hi there WPMUDEV, I can't acces my plugins anymore in my multisite! And the worst thing is, that I got this error JUST when I was about to upload the WPMU dashboard! (Dangit!)

This is the error I am getting:

Fatal error: Call to undefined function plugins_api() in /home/hogiedes/public_html/wp-admin/includes/class-wp-plugin-install-list-table.php on line 208

I have no clue what to do with it, could you guys please help me with this?
FIY: it's a WPMU wordpress installation.