Basically there are 2 ways:

1) Putting the database itself on a shared drive. Move your database now residing in $yourUsername\Documents\DVD Profiler\Databases and most likely "Default" to the destination of your choice.
Now in every client File -> Open Database -> Browse and open the database.
Important: only one client at a time can read the db, otherwise it gets corrupted.

2) Sharing over network: on your main-computer in Profiler choose Tools -> Options -> Sharing and share the db, read only or write access, your choice.
On every other client File -> Open Database -> Select Shared enter name ofdb and IP of the main-computer and open the database.
Important: the DVD Profiler on the main-computer has to be running. And only certain things work over sharing, watched date and personalize for  example, but editing profiles does not.

cya, Mithi