How can I close a panoramic sunroof that is stuck open & won't close?

The sunroof on this 2006 BMW X5 3.0l is fully opened and will not close. The motor runs and it will begin to go through the cycle to close but then stops . When I hold down the button to reset the sunroof by holding down the button inside of the car, the same thing occurs. How can I fix this? Do I need to replace it?