See in each Browser which version of Flash it thinks it has...
Perhaps it's disabled?
About Safari 5.1.7 and Leopard Security Update 2012-003
Learn about Safari 5.1.7 and Leopard Security Update 2012-003.
Mac OS X 10.5, Product Security, Safari 5.1 (Mac OS X 10.6), Safari 5.1 (OS X Lion)
Safari 5.1.7 for OS X Lion, Safari 5.1.7 for OS X Snow Leopard, and Leopard Security Update 2012-003 disable out-of-date versions of Adobe Flash Player.
Out-of-date versions of Adobe Flash Player do not include the latest security updates and will be disabled to help keep your Mac secure. If Safari 5.1.7 or Leopard Security Update 2012-003 detects an out-of-date version of Flash Player on your system, you will see a dialog informing you that Flash Player has been disabled. The dialog provides the option to go directly to Adobe's website, where you can download and install an updated version of Flash Player.
If you need to re-enable an out-of-date version of Flash Player, you can do the following:
1. Navigate to the /Library/Internet Plug-Ins (Disabled) folder.
2. Drag "Flash Player.plugin" into /Library/Internet Plug-Ins.
3. If the browser is running, quit and restart it.