Hi, I am having a problem completing the last puzzel. At least as far as I can tell, I have completed it, but the PUZZLE board still says it has not been completed and the sun dial doesn't change

You need to either use Arthur's workaround on the first page of this thread, or download the latest version of the game (v1.00.04 - see Arthur's post containing instructions in the list of sticky posts near the top of the post list).

I think I may be confused...possibly. I'm using 1.00.03 and a Mac. The last puzzle is showing as incomplete. I sent a PM to Arthur with my order info & the fact that I'm not using Windows. Was that the correct thing to do?

Yes, that was the correct thing to do, although it might have been better to say you are using the Mac version, rather than "not using Windows."