Please follow these instructions for installing the most recent version of Flash Player that supports PowerPC based Macs
1. Follow the instructions for uninstalling Flash Player on the Mac: Uninstall Flash Player
2. Download and extract the Flash Player 10.1.102.64 zip file
3. Navigate into the folder "/Flash Player 10.1.102.64/10_1r102_64/"
4. Mount the file "flashplayer10_1r102_64_ub_mac.dmg" by double clicking
5. Install using the normal procedure