GUI error: Could not find the main class. Program will exit.

From: thufir (thufir.hawat_at_mail.com)
Date: 12/30/04 

Date: 29 Dec 2004 22:54:28 -0800

"Java Virtual Machine Launcher
Could not find the main class. Program will exit." when foo.jar is
double-clicked from win2k.

"java -jar foo.jar" gives "Hello World!" on the terminal :)

why the error, pls?

/////////manifest.mf/////////////
Manifest-Version: 1.0
Created-By: JEdit
Main-Class: HelloWorldApp

/////////"jar -tf foo.jar"////////
META-INF/MANIFEST.MF
HelloWorldApp.class

thanks,

Thufir