Corel Painter X works fine on a PC but the Mosaic feature won't work on my MAC Book Pro running Leopard.

You were not helpful at all.  You were responding to a PC problem when I said I am using this program on my MAC.  By the way I am also a PC person and the Program (Painter X, and the Mosaic feature works fine on it).  I used the Painter Forum Magazine site and learned that the Development Team is aware that there is a bug in the  Painter Program and the Mosaic feature does not work with Leopard.
Why would I pay for a premium service with you when you don't know what you are talking about?