That symbol normally signifies the 'still waiting for root device' error. As a previous iAtkos release has worked for you, it indicates that you have not installed the chipset driver for your hardware (or the driver has changed).

If you boot in verbose mode using -v on startup, you'll be able to see the actual error message.

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 Mac OS X 10.6.4 Retail || Intel Core2 Duo E8200 2.66GHz || Gigabyte G31M-ES2L || GeForce 6600 GT 128MB || Realtek ALC883 Audio || Realtek RTL8169 LAN || Samsung SpinPoint F1 1TB HD || Sony Dual Layer IDE DVD RW DW-D22A || Apple Aluminium Keyboard || Mighty Mouse

 MacBook Pro || 2.4Ghz Core 2 Duo || 200Gb HD || 2Gb Ram || NVIDIA GeForce 8600M GT

 iPhone 4 || 16Gb