A. If in your boot.ini file your ARC paths consist of either SCSI() or SIGNATURE() you are using SCSI connection for the installation and the file NTBOOTDD.SYS contains the miniport device driver for the initial boot to communicate with the SCSI controller.
There is no such file as NTBOOTDD.SYS supplied with WIndows NT/2000 as its created during installation depending on your exact SCSI card.
This file is the specific SCSI miniport device driver for the SCSI adapter from which you are booting, renamed to
Ntbootdd.sys and placed in the root folder of the system drive.
To fix copy the correct device driver for the SCSI controller in use on the computer, and then rename it to NTBOOTDD.SYS at the root of the system partition (C: normally).
For example you would rename aic78xx.sys for a 2940UW Adaptec card (either from the NT installation media or better from the latest service pack if supplied).