Please try following steps :
1. Try deleting all data from following location on your machine and try updating again.
~/Library/Application Support/Adobe/AAMUpdater/1.0/. see if that works if not switch to next step.
2. Install the update manually.
For more help refer to Creative Cloud Connection update error - U43M1D204
Hope it helps.
Hi Anushri, thanks for the help, but I tried updating again this morning (before I read your reply) and it has installed OK this time.
Not sure what the problem was, but it is all OK now.
Thanks again for your help,