Kevin, the solution depends to some degree on where the water is coming from. If the ground, the answer may be to cover it with poly. If not the ground, the water is most likely coming from ambient humidity through all the venting you're doing. Of course, it could be a combination of the two. Test for ground dampness by laying down a square yard of poly for a couple of days (pile dirt on the edges to seal). If you find moisture under it, you know what to do. In humid climates, the vents should be blocked off, and in some cases a dehumidifier is necessary. You might want to run one at least temporarily to get things dried out, but stopping the moisture source is the only real answer. Regardless of where the moisture is coming from you want to eliminate your ducts as a condensing surface so make sure your AC ducts are air sealed (with mastic, not duct tape), and insulated with a foil or vinyl outer layer. This outer lay must also be sealed to keep moisture out or the insulation will just get soaked.