4 users unable to load java applet

Our help desk supports outside sales force with access to extranet including Web Reflections. I have 4 users who cannot run java applet to start app.
OS: 2 XP, 1 2k, 1 Win98, all desktops.
Connection: 1 dialup,3 cable modem on broadband
IE Version: IE 6 with full sp.

no commonalities. cannot reproduce problem on our own tech’s home pc’s. Any ideas?