Notes 4.5 running on NT 4.0

When using Notes connect agent iget the following error;

12/15/98 04:36:45 AM  Database: {file path name}
12/15/98 04:36:45 AM  NOTES: This database is currently being used by
someone else.  In order to share a Notes database, all users must use a
Notes Server instead of a File Server.

Any ideas ?