I uninstalled the older Flash Player and downloaded the "Install_Flash_player_10_osx.dmg. Once the installation begins at about the 16% point a message pops up saying the installation failed. This is the error message:
>>The following install step failed: run postflight script for Plugin <<
Another member (sisko8989) has had the same problem and he followed the recommendations of those who replied. I have done the same ... to no avail.
Might deleting a Preferences file help? Not sure which to delete.