Lauching Webstart applications from command prompt is not working in Vista

Tested build: http://j2se.east/plugin/1.6.0_04-nightly/2007-08-16.15_01

Platform :Vista (Utilmate)

To reproduce
============
1.Install Kernel JRE
2.launch notepad application from command prompt.
(javaws http://java.sun.com/products/javawebstart/apps/notepad.jnlp)
3.Notepad application is requesting JRE 1.3 download and fails to launch the appln.(screen shot attached :javaws_vista.jpg)
4.In Win XP this is working.In Vista,the same appln will work fine,if launched from the browser .
The same issue is found for Normal JRE also in some flavours of Vista .
Tested build: 6u5b02 promoted Build

Its working in Vista Home,Home Premium and Vista Enterprise.
Its NOT working on Vista Ultimate (jlab409.india.sun.com) and Vista Business (urti064.india.sun.com) machines.
Steps to reproduce:
1.Install 6u5b02 JRE
2.try to launch notepad from a command prompt.
3.Its requesting a previous JRE download
4.On clicking download button Appliaction Error dialog is shown with "Unable to launch the application."