Apple is pretty much leaving PPC users out in the cold now that they've completed the Intel transition. Try running the updates again (make sure to have backups of everything in case they break stuff too badly) and if you can get Safari 4 on there, it should fix the flash player as well. If that doesn't work, well, that basically means Apple is no longer supporting your machine. At some point you'll probably be forced to upgrade to a newer computer.
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