Update
=====
I still don't fully understand why this issue nuked the Playmaker menu, but for those who have experienced the same issue here's how I fixed it:
1. Open your project and then from the File Menu, hit Build Settings.
2. In the build settings menu, hit Player Settings...
3. Select the Player tab in the menu on the right
4. In the 'Scripting Define Symbols' entry, scroll through the text and delete any entry with "PLAYMAKER_ECOSYSTEM_BETA". Press enter after the entry has been deleted or it will not save.
5. Playmaker should bring itself back to life.
Strange error. I would disable the enable beta features from the ecosystem settings until this is fixed. Additional note, when I initially clicked the enable beta features, Ecosystem did it's usual "Unity is Compiling" thing and then pushed the error to the console. Either before or after the error was in the console, enable beta features was not able to be disabled (there was no checkmark next to the entry or anything to indicate it had even enabled itself correctly).