This information does not always mean error in your application or in bdb.
It can happen when you start the replication, and a site wants to connect to another while another has not listened on the port yet. In this case, the site will retry a little later.
It can also happen when you are closing the enivonrments. In this case, the not-closed or closing site may encounter this when it tries to connect the closed site. This is not error.
If this does make your replication fail to work, please provide more information about you application. Like the bdb version you using and the platform your application is running. It is better if you can describe how you are using replication.