Peer to Peer networking application prob

I have peer to peer network using Win98SE. Everything works fine except one particular application – Quickbooks. When the PC housing the app (and sharing with others) is using the application (even if the app is simply open and not currently being used, another PC cannot access the app, until first user quits the app. Any thoughts on how to troubleshoot?

Is this normal? I thought two users would be able to access the same appl simultaneously. Am I wrong?