Keith, This is a common issue with Dells. Many blame their buggy implementation of ACPI. I cannot prove it but having worked with them and seen it work / not work from release to release but working consistently on other intel server motherboards, I have to agree it may be Dell.
Try booting with the -B acpi-user-options=2 (NO ACPI) and then trying a init 5. If this works its most likely Dells ACPI implementation. -- This message posted from opensolaris.org
