While I realize that the dishwasher is still under warranty, I would call a dishwasher repair person and have them come out and diagnose the problem.
If the issue wasn't caused by faulty installation then maybe you could try and get the manufacturing company to come out and look at it.
Also, you could ask Sears if you have the repair person fix the problem are you able to bill Sears. This way you have a dishwasher that is hopefully fixed to your liking and you can reap the benefits of the warranty.