I have a 21 cu. ft Roper with freezer on top. A month ago I noticed water collecting on the top glass shelf of the refrigerator and water under the crispers. I put a small towel on the shelf as well as a small plastic container under the vent from the freezer at the back of the refrigerator. I saw your question today (I was hoping you had a solution) but decided to try to fix it myself. I did fix it and here's how I did it.
1. Empty the freezer of all food items and take out shelf in freezer. I put my food in a bag freezer chest I use for camping.
2. Remove 2 screws from floor of freezer. I used a 1/4-in. socket head driver.
3. Remove plastic freezer floor. When I did this I found some mold and about 1/4" of frozen and standing water mostly to the back of the freezer. I looked at the vent opening to the refrigerator section and realized the water was backing up and running into the refrigerator through the openings.
WARNING: The compressor coils are just behind the wall at the back of the freezer. Do not touch them with your hand (I did and lost a lot of skin off my finger) or anything that can melt.
4. Get a turkey baster and a pan of hot water. You're going to have to melt the ice away from the drain hole. At the same time, you'll melt the ice on the freezer floor. I used a plastic scraper to lift up the ice. Don't use a metal one because it could slip and puncture something, like a coil, in the freezer.
5. I used about 10 turkey basters of hot water before I could see the opening to the drain tube. This drains into the plastic pan under the refrigerator (see your user manual for location and how to empty). On about the 10th basting, I heard the water running into the pan under the refrigerator. I added 2 more basters of hot water to make sure the drain tube was open.
6. I washed down the freezer and parts with soapy water and bleach and reassembled the floor and shelf.
I don't know what caused the drain tube to block in the first place, but this will get it running open again.
Hope this helps.
John A Stikar, May 2006