WordPress.org

Please do as the developer suggests and do a manual FTP delete. Please do this first.

"You will need to manually delete the plugin via ftp. It can be found within /wp-content/plugins/ms-robotstxt-manager."

http://wordpress.org/support/topic/plugin-multisite-robotstxt-manager-problem-with-plugin-activation?replies

I found this after deactivating all my plugins, setting up a multisite by turning on networking. Tools> Networking, I had to change the .htcaccess file and the wp-config.php files. This all took about 30 minutes. It took 5 minutes to undo it. I had commented out what they wanted me to replace and kept a back up copy of the files just in case.

It took me 5 minutes to delete the plugin folder, edit the 2 files back to their original state, log out and log back in, reactivate my plugins, and fixed. Plugin is now gone.

Very good multisite plug-in for robots.txt manipulation with handy settings for network management. You can set the entire network at once or select individual sites, has presets.. Really cool!

A very time-saving tool for WPMU robots.txt installation and maintenance.

Works a real treat! I thought I'd have to build this myself until I discovered.it.