ppl, try to repair permission using disk utility, the restart and see if that helped. if does't u have to uninstall the flash player , reboot, reinstall it and repair permissions. i read somewhere when i bought my imac 27" that had the same problem, that sometimes flash installs in a corrupted way and using permissions repair fixes it. it worked for me with all my computers.
This is a solution that worked for me: Download and install public BETA Flash Player 10.1 from: http://labs.adobe.com/downloads/flashplayer10.html No permission repair or restart needed. This will be the last universal Flash Player version that supports PPC Macs.