Can you boot the systems without the AVA-2906 controllers installed in the machine?
If you can, remove the aic78xx.sys file along with the accompanying inf file.
Once you can boot the system, replace one AVA-2906 card in the system. Using the updated drivers
from the Adaptec website, try installing the drivers in the system.
If you once again get the blue screen once the driver is installed, you may have to force that specific pci slot to use a specific IRQ. This will be done in the bios of the machine.
You may also want to try setting the bios to NON-PNP operating system and boot again. That may be enough to get the system up and running on the available interrupts in the system.
Hope this helps,