Invoice can not be posted

Hi Guys,

Got this problem from 1 of my user.From wht i understand,it is related to MM and FI..

the case as follows:

I have keyed in an invoice (through Logistic) but there is a message at the bottom

on the last screen and I cannot save even though the debit and credit is tally.

Please refer the message below:

4500031832 00001 not copied (moving av. price for material PW822846 would be negative)

Can you suggest how to solve this problem?

Sorry to bug u all,all the time...newbie in SAP,need to learn everything from scratch on my own...

TQ all for helping..u guys rocks!..