Use the "U2W v1.02f3 Flash Utility" to update your Adaptec 2940U2W SCSI Accelerator board to the latest version of the driver. This driver includes a fix which allows it to work under MacOS 8.5.
Please refer to the "Adaptec Flash Utility.pdf " document for instructions on how to use the "U2W v1.02f3 Flash Utility".