Doesn't really seem to be a NVIDIA question because it appears your not even booting at all. Is your hard drive light flashing durring boot? Anyway, assuming your not booting try below.
One of the differences from old Solaris to todays new Solaris is they default to ACPI turned on and DMA turned on. So I suggest to try one of the following or both:
where the acpi is now turned off
and dma is off
please refer to the link for detail information on acpi:
Both items can be set using
or manually be editing the text file