Here is the reply I got back form Miele and it worked for me:
Thank You for your e-mail. The "water system fault" is a common error with the CVA615. This means that when you put the water container into the coffee machine the valve open prematurely and drained the water into the bottom pan. If you open the door and take out the water container you will find a hole about the size of a half dollar. If you put your finger in this hole you will find the water that is causing the fault. Do you have a turkey baster in the kitchen? If not get one at your local super market. When you have a CVA615 it can come in handy and you may need it again sometime. What you will do is put the end of the turkey baster into the hole and extract the water. Once you remove as much water as possible leave the door open and allow the unit to dry out, around an hour. The float will drop and the water system fault will disappear. You can now refill your water container and carefully replace it into the coffee machine so that it properly fits into the valve receptacle.
Please contact our Technical Support Department at (800) 999-1360 if you have any further questions or concerns.
Tami Scheibach, January 2008