Microsoft Knowledge Base Article 312862 contains the following summary:

File Replication service (FRS) is a multi-threaded, multi-master replication engine that replaces the LMREPL service in Microsoft Windows NT 3. x and in Microsoft Windows NT 4.0. Windows 2000-based and Windows Server 2003-based domain controllers and servers use FRS to replicate system policy and logon scripts for clients that run Windows Server 2003 and earlier. You can also use FRS to replicate files and folders between Windows 2000-based and Windows Server 2003-based servers that host the same fault-tolerant Distributed File System (DFS) root or child replicas.

This article describes:

How the deletion of FRS objects and FRS attributes occurs.
How to detect missing Server-Reference attributes and member objects in SYSVOL replica sets.
How to repair missing attributes by using null Server-Reference attributes as an example.
How to repair missing objects by using missing member objects as an example.
How to repair missing connection objects by using existing connection objects as an example.