Microsoft Access Database Sharing

I have set up a database on a shared drive for everyone to access the database. This is a peer-to-peer network setup. The database is set to open as shared by default(tools, options, advanced, shared). When any of the computers open the database, none of the other computers can open the database except for the server.

So, if the server or any remote computer opens the database first, the other remote cannot open. I put this same database on another network that is supposed to be set up the same (same company, two stores, same company set up the network) and it works fine. Help!