Error No exchange rate for exchange rate type P on 6.08.2005: AUD-->USD

Hi,

AT the time of Reprocessing of confirmations with errors in calculation of actual cost (COFC). When I execute this transaction with some order that time I am getting error for all postings for networks since 26.08.2005"Error No exchange rate for exchange rate type P on 6.08.2005: AUD-->USD" The error stops the posting from appearing on the monthly billing report to our finance dept to enable rechange.

Can any one of you please let me know what can be the work around for this problem.

Regards

Hema