RMA - Error creating return

Hi,

SQL2008/Sage 300 V6.0 PU2

Trying to create a return from an invoice that has two items on the original invoice.
When adding the items to the return - item 1 is fine but item 2 gives the error "Description: Invalid Entry. RMA Quantity for this item DIN 6325 8X40 exceeds difference between invoice quantity and total quantity returned."

Any suggestions??

TYIA