As requested we tried network activation and it generated the same errors as initially noted. However it appears activated.
I was able to go into the site (sandbox.darylcagle.com) and create an instance of the plugin via the admin UI. However, if I disable it on a network wide level and go into the site plugins (sandbox.darylcagle.com) and activate it, it redirects to (sandbox.politicalcartoons.com) and activates it on that site instead and is not available on sandbox.darylcagle.com.
The support account I created for you to log in with has super-admin privileges so you can see for yourself what is happening.