Problem in BAPI_OUTB_DELIVERY_CONFIRM_DEC !!!

Dear all,

I used BAPI_OUTB_DELIVERY_CONFIRM_DEC to PGI. But I can't use vl09 to cancel it. The error message is 'Cancellation of goods movement from decentr. systems is not possible'. What's the reason ? Can anybody help me ? Thanks very much indeed.

Thanks and Best Regards.