Actually caligraphics there are only 3 layers in that file, I was trying to create a 4th.

Emo yes I had tried selecting objects even added new ones just for this purpose, but always recieved the same error.

I'm thinking that perhaps the CPS tools may have something to do with it? But I'm not sure what.

Since I first posted this the has been modified on an Mac (I'm using a PC) all the layers have been deleted and the file renamed. It's now back on my system and I just tried to create a layer for the hell of it and got the same message except now the display number is at 1 rather than 21.

Oh and all geometry created with CPS have been deleted.

Thanks for the suggestions!