[WPMU DEV Dashboard] WPMU Dev Dashboard App No Longer Installed on Website

An installation of the WPMU Dev Dashboard has mysteriously disappeared from the website bcrft.com. I tried to reinstall it this evening and I received an error that the installation failed because it already existed, but it's not listed on the WP Admin Dashboard. I'm not sure why this has happened although I have been experiencing some minor glitches with the site itself which is built using a Layers child theme called Craftsman created by a developer who no longer supports it. Please let me know what steps I need to take to correct this situation. I'm a designer not a developer so I'm afraid I really need your support and expertise in guiding me through this situation.