Yes I had this problem the other week. I can't remeber where I found the answer now, but the problem is with the web address. They have changed it from cfa-www.harvard to
www.cfa.harvard. The full address is as follows:
http://www.cfa.harvard.edu/iau/Ephem.../Soft06Cmt.txt
To update the program, edit the file 'extres.ini' in the main program directory (C:\Program Files\ciel if you installed it in the standard place).
Replace all instances of 'cfa-www' with 'www.cfa' and it will work again.
I'm sure I don't need to say backup the old 'extres.ini' file first