Please HELP!!! URGENT!!! java.io.IOException: Connection failure with 407

Hi,
I need to give a demo on a program next week and i am getting this error....
I am using tomcat 4.0.3, while running my Applet-Servlet program.
If i run my program in the same computer i works fine...
But i am trying to run the program from another computer and getting the following error.
There is nothing wrong with the null pointer....I am definitely sure about this....
I think the problem is with the security (java.io.IOException: Connection failure with 407)...
Thanks in advance....
Error:
=========================
java.io.IOException: Connection failure with 407
Exception occurred during event dispatching:
java.lang.NullPointerException
at scanstation.LoginScreen.displayLogInInformation(LoginScreen.java:220)
at scanstation.LoginScreen.jButton1_actionPerformed(LoginScreen.java:151)
at scanstation.LoginScreen.passwordTextfield_actionPerformed(LoginScreen.java:255)
at scanstation.LoginScreen$4.actionPerformed(LoginScreen.java:123)
at javax.swing.JTextField.fireActionPerformed(Unknown Source)
at javax.swing.JTextField.postActionEvent(Unknown Source)
at javax.swing.JTextField$NotifyAction.actionPerformed(Unknown Source)
at javax.swing.SwingUtilities.notifyAction(Unknown Source)
at javax.swing.JComponent.processKeyBinding(Unknown Source)
at javax.swing.JComponent.processKeyBindings(Unknown Source)
at javax.swing.JComponent.processKeyEvent(Unknown Source)
at java.awt.Component.processEvent(Unknown Source)
at java.awt.Container.processEvent(Unknown Source)
at java.awt.Component.dispatchEventImpl(Unknown Source)
at java.awt.Container.dispatchEventImpl(Unknown Source)
at java.awt.Component.dispatchEvent(Unknown Source)
at java.awt.LightweightDispatcher.processKeyEvent(Unknown Source)
at java.awt.LightweightDispatcher.dispatchEvent(Unknown Source)
at java.awt.Container.dispatchEventImpl(Unknown Source)
at java.awt.Component.dispatchEvent(Unknown Source)
at java.awt.EventQueue.dispatchEvent(Unknown Source)
at java.awt.EventDispatchThread.pumpOneEventForHierarchy(Unknown Source)
at java.awt.EventDispatchThread.pumpEventsForHierarchy(Unknown Source)
at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
at java.awt.EventDispatchThread.run(Unknown Source)

hi sam,
what is at line,
at scanstation.LoginScreen.displayLogInInformation(LoginScreen.java:220)
i mean what is the line 220 in LoginScreen.java?
also, it might be helpful if you paste your code here...
thanks
maulin.

Hi,
Thank you for your reply...
displayLogInInformation returns a Vector...
Basically this is what's happening ...
In the browser the user inputs the username and password... i am taking that username and password and checking in database if its correct...
If it is then it displays next screen...
The problem is not with the NullPointer Exception...
I think the problem is with Some sort of security. I am able to run this program in my computer#1. But when i run that prgram from computer#2 I am getting this error...
I can access the tomcat server of Computer#1 from Computer#2.

well,
it is giving the NullPointer exception...so we can't ignore that...
it might not because of the application's code may be but there is something wrong somewhere...
i am unable to think of possibilities..
regards
maulin

I guess that there is nothing to do with null pointer exception. The connection was refused and since the applet could not retrieve the data, the object reference is null. There would be possibly a try - catch block across the code that communicates with the servlet.
HTTP/1.1
407 Proxy Authentication Required
You must authenticate with a proxy server before this request can be serviced.
Please logon to your proxy server and then try again.
Since in system A you won't be using the proxy, so no authentication is required.
hope this helps
----------------
vijay.

more help can be given if you can give a part of the codes..
Lupo