I eventually muscled my way through it. The first thing I did was manually activated the plugin via the databasemanually activated the plugin via the database. Next I went back to the subsite to verify that the plugin was activated. It was not.
So I tried activating again. Now I was getting an error in relation to memory being exhausted. This was caused from the large amount of data for my CPT and taxonomy.
I had to export my post and taxonomy tables from the database, then delete everything, before I was able to activate the plugin.
After the plugin was active, I was able to import the posts and taxonomy terms back into their respective tables.
