It's been a while since I ran Leopard (my Mini has Mountain Lion) so these steps may or may not work:
There is only one version of Flash Player for Mac (Intel), so the one you download will be correct. If it's for PPC it will say so specifically in the DMG file name.
Download the DMG (if you don't already have it) http://download.macromedia.com/pub/flashplayer/installers/archive/fp_10.3.183.90_archive.d mg
DO NOT mount the DMG or run the installer yet!
Go to: Mac HD/Library/Internet Plugins
Trash the Flash Player.plugin file from there
Go to: Mac HD/Library/Application Support/Adobe
Trash the Flash Player folder (the whole folder)
Empty the trash
Mount the DMG and run the installer.
BEFORE opening any Flash content in Safari, open Safari>Preferences, and check the Security tab to make sure "Allow all other plugins" is checked.
Thank you so much for replying. I've got it now. Apparently the "mac only" dmg was defective or missing something; it was only 6.6 mb. I went back and got the whole package, about 61 mb. That one worked fine.
I'm starting over with a new hard drive, so don't have to worry about older versions.