16-bit MS-DOS Subsystem Error Quick Fix.
When trying to install or run an application on Windows XP you recieve the following error:

16-bit MS-DOS Subsystem path to the program that you are trying to start or install config.nt The system file is not suitable for running MS-DOS and Microsoft Windows applications. Choose 'Close' to terminate the application.
or;

16-bit MS-DOS Subsystem path to the program that you are trying to start or install C:\Winnt\System32\config.nt The system file is not suitable for running MS-DOS and Microsoft Windows applications. Choose 'Close' to terminate the application.

or;
16-bit MS-DOS Subsystem path to the program that you are trying to start or install C:\Windows\System32\Autoexec.nt The system file is not suitable for running MS-DOS and Microsoft Windows applications. Choose 'Close' to terminate the application.

Download and run this program to fix this problem.