Older application doesn't run after update

From: David (David_at_discussions.microsoft.com)
Date: 02/16/05 

Date: Wed, 16 Feb 2005 02:15:04 -0800

Hello,
I got windows 2000 server here in the company, and we use an old accounting
application to make invoices, but after I installed the last updates the
application doesn't work no more.
I got this message.
16 But Windows Subsystem
C:\Winnt\System32\Autoexec.nt. The system file is not suitable for running
ms-dos and microsoft windows applications.

Someone knows how can I solve this?

Thanks in advance.