Problem Running J2EE Application in NWDS12

I am running Netweaver Developer Studio Version.

SAP NetWeaver Developer Studio

Version: 2.0.12

Build id: 200505090134

I have developeed a new J2EE Enterprise Application. I have successfully built the application.

When I run the application via the

Run --> Run --> J2EE Application path, and then select a JSP, I receive the following error.

"Could not find executable for file extension = htm"

This prevents the application from running. I have checked that a file association exists against .htm, which is Default HTML Editor.

Can anyone advise the cause of this problem

Thanks