This may or may not be the correct answer...
One thing I recently learned was that AE and PPro do not work the same way. Hence, Colorista II does not behave the same in PPro as it does in AE.
You'd probably have better luck resolving your issue by contacting Red Giant.
I'm had the exact same issue. So I contacted Red Giant directly and asked why I was receiving this error. Unfortunately it is a bug in the program and apparently they have been aware of it and are currently still working to resolve it. There is a work-around, however, for the time being they said to revert back to the previous version of Colorista (one previous to their latest release) and you should no longer experience the issue. Keep checking with for the fix or you can submit your report to them and they will keep you on file and contact you when the fix has been made.
All the best.
Yes that is correct, ist a bug.
Contacted RG also, got the same reply.
The same goes for the new Magic Bullet Looks 2.
They both work perfectly in AE its just Premiere.