SQL Server 2005 Replication Stops after a minute without an error
SQL Server Replication is a notorious error hider.

Usually if replication just stops, a problem occurred and there is on place where you can see what that problem is. All other places you might look at show no sign of trouble.

Places to include when hunting for errors:


The replication monitor
The job history of each job involved (Look at the history. Even the SQL Agent Monitor hides a replication problem every once in a while.)
The SQL Server error log
The windows event log


3 and 4 are rarely needed. 2 is usually all you need to look at to find the problem if 1 did not help.

There is a lot more information about potential errors and how to identify them in my replication stairway articles. Particularly in Level 10.