Is it coming out where the dipensor drawer goes in? Or is it coming out of the left side of the unit?
Can you remove the drawer and hold your hand over the opening and start a cycle will it over flow here also?
If it is left alone for a minute will the water drain into the tub?
With the drawer removed can you get your hand in and go to the bottom left and then towards the front. There should be bars on the exit hole that will catch large items. Below is a picture of what the dispenser looks like. This should help aid you in knowing where you are going.
Let me know what you find. Thank you...