On the JR packs I have, the orange wire is tucked into the shrink wrap from the connector, but it doesn't actually hook up to the battery. As Jett said, the orange wire is there simply because that way they only have to stock one type of wire rather than keeping 2 strand and 3 strand around.

Check these things:
1. Use a voltmeter to see if you have voltage at the plug on the battery without havign it plugged in. Is there a voltage reading? No voltage means a broken connection somewhere on the pack which means stripping the shrink wrap to inspect.
2. Check the polarity, for JR, the red should be in the middle.
2. Check the little plastic tabs that hold each connector. As was said above, if the plastic tab is flexed up, the black or the red socket may be slipping in the plug, preventing good contact with the charger pin.
3. Check the socket fit. Use a small flat blade to lift the plastic retainer slightly, then slide the sockets out of the plug. Test fit the sockets on the charger pins one by one (with the charger unplugged) to make sure they fit snugly, If they are loose a light squeeze on the socket body can fix it.

One of these 4 things should get you there. Try them and post again to let us know what you found.

Duke