I had the exact same problem and was at the dealership today to have it fixed under warranty. Mine was plugged and the water was gathering, then overflowing into the car. It's in a very tough to get at spot, and the actual VW repair sheets show the subframe disassembled to fix it when the mechanic checked online. However, the tech is not just a good mechanic but a smart dude, and was able to use a coat hanger and bend it to get up into the subframe and unplug the problem. I was watching as he did it thinking this isn't going to work, but all's well. He shop vac'd the carpet and dried it, then ran the ac and no more water! Wish I could explain to you how to do it, but even watching it, you'd need to get the T on a hoist or somehow get underneath it and reach way up in there to get at it.
good luck!