Net Express 3.1 is certified only under the following environments:
Windows 95 (Windows 98 recommended), Windows NT V4.0 (Windows NT Service Pack #5 or later), Windows 2000, or Windows XP Professional.
The only version of Net Express or Application Server that is certified under either Windows 7 or Windows Server 2008 R2 is Net Express 5.1 or higher.
If you need support for more current operating systems like Windows 8 or Windows Server 2012 then you should look at moving to Visual COBOL.
Thanks.