Have you recently hung anything on the wall (in both rooms that the door separates) that's WITHING about a 3' distance from the edge of where the door goes in the pocket? If so, it's quite possible that the nail or screw or whatever has 'fixed' the door in a more permanent 'position', (i.e., fixed in the pocket!) If this is the case, remove the nail/screw from the wall and open the door to see the damage.
If this isn't the case, NEVER hang anything on EITHER side of the pocket's wall that's within 4' of the the pocket's leading edge. Next, contact your Builder for some help. Maybe he's in the area and he'll stop in. If you have a New Home Warranty, now's the time to use it. At worst, the jam on the edge of the pocket may need to be removed to see inside.
Please let us know what the cause is so we can put it in our 'bag of tricks'. My best to ya and hope this helps.