Hi, I'm not sure if that edition is still supported, check here:
Following is the Archived Versions:
If you find a version that works, keep in mind you must Uninstall any version that is already Installed first.
This is a Mac Troubleshooting Guide that may be helpful. I know it's for whatever current version of Flash Player is out, but I would think the basics may be the same. You probably can tell by looking it over.
Hope that helps,
I had your same problem today because of a piece of sheet music I was trying to print told me I needed to upgrade my Flash player. I have the same exact operating system and computer. I tried downloading every one until one worked. The archived Flash 10.1 (not the debugger version) was the one that worked for me and for some reason I had to reinstall my Shockwave Player 18.104.22.1680. Now, all my plug-ins are working fine and I was able to download and print that sheet music!!! Hope this helps. Good luck!