Also, computers running Windows Vista (vs. XP) can't access the mainframe (green screen) because FedEx has chosen not to comply with Vista standards yet.

Vista computers will download and run the mainframe plug-in (applet?) but once the window opens, it won't be able to connect to the FedEx mainframe - that might be the syntax error you were getting.

Try the same thing again on an XP machine (if you still have one) and that should work.