invoice journal reversal in AX2012

Hi,

when we try to reverse an invoice journal, it gives following error message:

Reversal denied. Account number 2110201011-Contracting----- is journalized.
Reversal denied. Account number 5112201001-Contracting-----1977 is journalized.
ledger transaction type Ledger journal for account 5112201001-Contracting-----1977 cannot be reversed

Any idea?