If you’re using the ATTO card along with Snow Leopard then the 2.41MP driver on their website is compatible with 10.6, but they have yet to update the website to reflect that it is. These are the drivers for 42ES coupled with the EMC Clarion system:
http://attotech.com/product.php?model=80

You may want to check with Tech Support, but it appears the latest 10.5 drivers will work with 10.6

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