Problem with collect funding

Hi, I have a problem. When I try to collect funding in a project I receive this pop up message:

{“status”:”fail”,”message”:”Receiver PayPal accounts must be unique.”}

Can you help me please??

This is the project: http://geofunding.es/project/un-elefante-en-mi-lavadora-la-chica-charcos-the-katiuskas-band/

Thanks