Is your Neato stopping with an RPS error?
Often times the RPS error occurs when the laser mapping sensor has gotten slightly dirty or dusty. You may want to try to clean it with compressed air. The sensor is at the top of the robot, at the rear under that little projection just to the side of the control panel/display. You really want to clean underneath the frame all around its circumference.
This usually helps illiminate RPS errors.
Is your robot new and clean? Do you possibly have reflective surfaces on the walls or many obstacles? You may want to troubleshoot your robot by letting it clean in a fairly simple room. A rectangular or square room with few obstacles and furniture. This will help determine if something in the robots environment prevents it from functioning properly.
If the problem persists, contact RobotShop or Neato Robotics.