Part 622 on this diagram of your unit parts is the drain trough. It has a hole in it there the drain tube should be which may be stopped up. Replacement parts for GE CTX16CAXGRAD | AppliancePartsPros.com

Ok, I've located the drain tube, which is of course full of ICE. The big problem is that the tube does not exit the fridge. It must run inside the back wall. Any suggestions on clearing this of ice? By the way, my food comprtment must be set too cold as the water bottles against the back wall tend to freeze. So, I'm sure that the entire drain tube must also be frozen. HELP!!!!

Woodchuckie, that worked great. I used the hot water. Once the top quit filling with water, I assumed it was clear. I put the thing back together before I got your last post. If if starts happening again I will deffinatly use the turkey baster. I must say that what was happening was, the drain tube got plugged. Then, when the trough would fill up with ice and water, it would spill over into the freezer and collect under the elevated floor. When that was full of water and ice it would overflow through the venilation hole and run down into the fresh food compartment.

Thanks for all the help from all the posters. I know where to come back to in the future! DIY's Rule!