Sage 100

We are on Sage 5.41, Can Multiple users enter a Cash Receipt at the same time with different deposit numbers???

I'm a new user of Sage 100 ERP 2013 (v 5.00.8.0) and am trying to post cash receipts. I have a client using three checks to pay one invoice. I entered the first check fine, but when I try to enter the second check and apply it to the same invoice it says…