2008 Nissan X-Trail Diesel particle filter

First the diesel particle filter warning lamp came on, quickly followed by the engine management malfunction light. The dpf light has been reset but the engine management light remains on. I have now noticed that the cruise control won't work, although the lights on the steering wheel do function and indicate that the cruise control has been engaged. So far all work has been done at a local garage. They are now saying I will need to take the car to a dealership to clear the warning light. Also, do you think the malfunction of the cruise control is related to the dpf and engine management unit malfunction? Thanks, Alan