Volkswagen: air conditioniner smell, pollen filter, vent system

Question
I have VW Beetle 2000 and when I turn on the air conditioner it smells like “cat pee.” The odor is very strong even after you run it for awhile. We do not have a cat and keep the car in the garage. I just recently purchaed the car (Nov 2004) and I did have the radiator replaced. I live in Texas, but up until recently I did not use the AC very frequently. Any ideas what this smell could be?

Answer
it may be that the air con needs some anti bacterial spray running through the vent system. another problem is that sometimes rodents get into the engine bay and work there way to the pollen filter. they tend to use it to nest in. to check this, you need to dismantle part of your interior dash board as the pollen filter is located on the passenger side under the trims. to do this i advise you get a manual. sorry about delay, moved house and computer blew up