i would say its the immobiliser unless you have lost the chip out of the key, try this site for parts
http://www.electrexworld.co.uk/peugeot-scooters-electrical-parts-10125-0.html
they may be able to help you out
adam bike doctor(of milton keynes motorcycle centre)
February 2011
howtomendit.com for free repair help, information and advice.
