If this is being used by five users on a network, you really need to think about splitting the database in to backend and frontend if it's not already - that will stop a lot of the conflicts. As Adrianna says, make sure that the default open mode is shared and also that the default record locking is set to EDITED RECORD.
Using the database splitter wizard, found under Tools>Database Utilities>Database Splitter. Split the database into backend (data) and frontend (forms, queries, reports, etc). Put the backend in a shared folder on the network and either give everyone their own copy of the frontend on their PC (my preferred option) or have everyone access the same frontend through the network too.
If you don't have it split at the moment, you are likely to run in to a a lote of problems - which could include the corruption of the database. Search the formum for Split Database to find a mountain on the subject.