Thanks for taking the time to reply, Team.
In another related thread
, realitybytes suggested that I tried getting the debug information from the browser and see whether the exact problem could be pinpointed. As I haven't access to a working Mac that can run OS X here, I asked Mac users on my forums to help me to obtain this information. The helpful volunteers have come back to me with this disappointing response:
So, it is back to square one: problem remains unresolved. :-(
Is anyone else able to help, please?