Error Message in A/P Posting Invoice

Hi,

While posting invoice in Acct Payble, it’s showing an error message

“”"Voucher 702 date 04/19/2012 Acct 141020 Amt currency 500.00,Amt mst 500.00

Alternative amt 4545.45,currency usd text"'

What I have to do here???

Regards

Saby