if you have installed Service Pack 1 for Windows Server 2003.
The tools Repadmin.exe and DcDiag.exe are useful in troubleshooting this problem.
As per Microsoft: "Event ID 1862 is logged when we have domain controllers not replicating between sites. There is a specific misconfiguration where we created Active Directory sites but the site was not in the site link, and we now have a specific event that captures that misconfiguration". See the link to "Upgrading Windows NT 4.0 Domains to Windows Server 2003" for additional information on this issue.
This is a status report given in Windows 2003 to let you know if your Active Directory DNS partitions are replicating properly. This message also gives you statistics about the partition being replicated.
The domain controller has not been able to replicate other objects from another site within the forest. Ensure proper configuration by validating domain trusts throught domain.msc.