Negative cost amount for receipts is not allowed. Ending a production

Hi 

We did a production and in one of my picking list the cost war wrong for one part, so we did a -1 to fix the part and we redid the consumption of one.

did the report as finished with no error but when i try to end i get Negative cost amount for receipts is not allowed.

i looked at the values in the debugger and i see that the costamountposted of my report as finished voucherphysical is negative.

How can i do to end my production.

Thanks for your help