Unable to play videos on the BBC web site.

Running an iMac (Mac OS X 10.9.1) with Safari (7.0.1) and Flash Player 11.9.900.170 I get the message "This content doesn't seem to be working. Please try again later" when trying to run any videos (including those in iPlayer) on the www.bbc.co.uk web site.

On a Macbook Pro (Mac OS X 10.9.1) with Safari (7.0.1) and Flash Player 11.9.900.117, the videos and iPlayer content all run normally.

On both machines, video files from other sites run normally.

I have removed and re-installed Flash Player 11.9.900.170 on the iMac, checked all the advice from your Forum pages, but can find no way to improve this situation.

Any advice gratefully received.

Tony Moss