Wow, I never really noticed but those plugins aren’t showing up in my Premiere either. I have the FilmImpact.net demo/free plugins (but not the purchased versions). But in my case the plugins that were killing Colorista I and II turned out to be Knoll Light Factory.
If I removed the Knoll Light Factory plugins, Colorista would load. But with it there, Premiere reported the following in the plugin log:
Loading C:\Program Files\Adobe\Common\Plug-ins\7.0\MediaCore\Magic Bullet Colorista\Colorista_II_x64.aex
Loading from disk...
The library could not be loaded, so the plugin is set to Ignore.