VW Window Lift Channel - Rabbit, Jetta, Scirocco, Dasher. This is the window lift channel that attaches to the regulator and holds the glass. One of these is required per door. They rust and corrode allowing the glass to separate from the channel leaving your window not working. To fix the problem, replace this channel and if necessary the rubber seal that goes between the glass and the channel (sold separately).
Now that you'll have your window actually working with your new VW window lift channel, get the rest of your door working too. If you are replacing your channel and you would like to replace the rubber as well, and if you notice the door is wobbly when you close it, replace the latch striker at the same time.