I started a project in After Effects CC 2015 and I was able to rename bones once I created them. I now get error messages when I try to do this. I have also tried naming the puppet pins first and it still gives an error.
Oh and tried renaming the expressions and this doesn't help either

I have sadly updated to CC 2015.3... and I'm on a Mac.
Is there any thing I can do?
Many Thanks
Tim