This message: REMAP is always the result of a duplicate MSKU. Once you change the affected MSKU; you can continue.
If your MSKU was: 2014-01-31-B006K3VGBS change the MSKU up beyond the end of your batch; for example: 2014-01-310B006K3VGGS-1
Below are directions for changing the MSKU in the ADD ITEM TO SHIPMENT(S) pop-up.
To change the MSKU simply double click on the MSKU field and edit the existing MSKU to create a new one.
This second video shows the same process while importing from the buylist.