Magic Chef HVAC water problem

I have a Magic Chef HVAC unit in a hall "closet" that is dripping water by the gallons. It has not been a problem until a few days ago when the unit froze up. We had a tech come out and fill the coolant so the unit is running but there is water coming from around the drip pan and running down into the air intake "crawl space" under the unit. I have cleaned out the drain and can actually see with a flash light thru the pipe all the way to the coil...all is clear. I took the cover off the coil and scraped out a bunch of sludge from the pan (rusted pretty bad) and watched the water level while the unit was running. It does not appear to be overflowing the pan. I guess it could be rusted out but can't see any obvious holes. I noticed the insulating material glued to the inside of the box around the coil is wet down near the pan and at the far end of the coil where it is up against the end of the coil. I don't know if it is normal for that material to get wet or if it might be the result of the freeze up the other day. Any suggestions what to look for? Can the pan be replaced and if so, how do I get it out without damaging the coil? I was wondering if the insulation material might have gotten wet during the freeze up and now is acting like a wick, syphoning the water out of the pan and if so would drying it out with a hair dryer possibly fix the problem?

HELP!:help: