[Chugalug] Corporate portal doesn't work with Linux (or Firefox)

[Robert A. Kelly III]

The Convergys corporate intranet is supposed to be available over the
internet at my.convergys.com, but it doesn't appear to work on any
browser on Linux. Opera and Chrome work only when running on Windows and
Firefox never works even when it is running on Windows. When it works,
the site prompts for a username and password, but with any browser on
Linux or Firefox on Windows it simply gives:

HTTP Status 401 -

type Status report

message

description This request requires HTTP authentication ().
Sun-Java-System/Application-Server

without prompting for a username or password. Can anyone tell why this
is happening or if there is a way to login from a Linux machine?