When click on Add New in the Site Wide Text Change plugin nothing happens


Installed SWTC Plugin by coping file and folder per instructions in the mu-plugins as follows:

site-wide-text-change – goes in /wp-content/mu-plugins

/sitewidetextincludes/ – goes in /wp-content/mu-plugins

However, when Add New button is clicked nothing happens.

WPMU 2.8.4a

What I’m doing wrong?