How can I fix my fridge freezer that's leaking water? Defrost problem?

I have a old fridge, 2 door side by side with freezer on the left side. Sorry I don't have the model details. It's leaking and the water is running down and out the freezer door. Ice forms at the bottom of the freezer and when it melts it starts to leak to the floor. At first we thought it was the drip pan which we replaced but it's still leaking from time to time. Does this sound like a problem with the defrost? Thanks.

Sue
February 2006