This can happen if the Adaptec card has older firmware installed. The best firmware to be running on the Adaptec 2940UW and 3940UW, is version 4.1, and using the Adaptec Power Domain Control utility version 5.1. (This was written 4/3/01)To reinstall or update the firmware onto the Adaptec card, download the 2940UW v4.1 Flash Utility from adaptec.com Reboot with extensions off, and run the Flash Utility. Then reboot the computer again.On the same site, the PowerDomain Control utility v. 5.1 should be available for download. Use that to limit the data transfer rate of the SCSI to avoid "PCI Bus Too Busy / 6042" errors in Pro Tools. After installing the 4.1 firmware and rebooting the computer, launch PowerDomain Control, and under the "Advanced" Tab/Window, set the transfer rate to "Fast - SCSI:10".Lastly, make sure that the version of the ATTO Express Pro Tools application that you used to initialize the Hard Drives was 2.32, or a version deemed compatible by Digidesign (check digidesign.com).