Difficult to say what the cause is with the information you supplied. It could be any number of things. Is there a message such as "POINT LEVER MISSING" ? You said the point lever pulsed. I have never seen a point lever pulse. Do you mean the points are constantly changing? If that is the case it would indicate that the AI is unable to navigate a path through the junction. Usually you can get round it by changing the position of the points either in surveyor or driver. Another solution if changing the normal position of the point switches is not possible for operational reasons then placing an invisable signal to reduce the number of point switches between signals will work. Common Reasons for an AI driver stopping are a point motor or lever missing, a track direction marker facing the wrong way, A gap in the track and the one I mentioned. There are ways to fix all these but if there is a message from the driver it would be helpful to know what it is. Awaiting your reply.