If that fails to resolve it, you may need to also delete the Flash Player folder from your [User]/Library/Preferences folder
Toaccess it from Finder, hold the "Option" key and click Go>Library
Holding the "Option" key
Thanks - I did perform the 'clean install' as well as the above suggestion and it was OK for a while, but now the same thing is happening again. Is there a longer term solution??
Try creating a new user account (admin) and try Safari under that account. If it works without any errors, you need to repair permissions on your account using Disk Utility.