Currently Being ModeratedDec 4, 2012 5:58 PM (in response to stephnmillie)
Adobe no longer suports an obsolete OS like 10.5. 10.5 Leopard was based on Power PC code and was written to be able to run on both Power PC and Intel processors. 10.6 Snow Leopard has completely rewritten code and only runs on Intel Macs.
The 10.6 Snow Leopard DVD is back in the Apple online store. You can now get it for $19.99. http://store.apple.com/us/product/MC573/mac-os-x-106-snow-leopard