Resolution Steps: Apparently this error message, or a similar one mentioning config.nt, can occur when one of the following files is missing or corrupt:
The erorr can occur when installing or uninstalling a program.
In my case Autoexec.nt was missing from the C:\WINNT\System32 directory. Looking in the C:\WINNT\Repair directory I found that Windows had automatically made a backup copy of Autoexec.nt, so I just copied this into C:\WINNT\System32 and the problem was fixed.
Note: The C:\WINNT directory on my computer may be C:\WINDOWS on other systems. Substitute as necessary when following the above instructions.
Note: If you can't find a copy of the missing file in your Repair directory, use your original Windows OS disk to get the missing files. At the command prompt type the following commands:
expand e:\i386\config.nt_ c:\windows\system32\config.nt
expand e:\i386\autoexec.nt_ c:\windows\system32\autoexec.nt
expand e:\i386\command.co_ c:\windows\system32\command.com
Substitute "e:\" for your CD-ROM driver letter, and "c:\windows" for where your OS is located.