the drip seems to be around the seal, rather than in the plastic - it was just accumulating on the plastic.
i have taped over the area. i know that this defeats the purpose of the drainage, but my prerogative is in keeping the water off of the floor. and, i suspect that the issue is upstairs, anyways.
i'm going to guess that the seal probably needs to be recaulked. but that the issue is probably really in the furnace.
j