Purchase Orders not creating

Hi,

Has anyone experienced requisitions not creating a purchase order? The status is Approved and the Fund status is Reserved, so it's gone through all the needed workflow approivals. We now have over a hundred since we launched back in June and they are not in in Process requisition or incomplete PO. The only workaround is to have our clients duplicate the requisition and resubmit. The other terrible thing is that we cannot cancel the requisition.

Thanks,

Anne