I am always on the Technet forums replying to the other folks having issues with the Active Directory. The most commonly asked question is about Event ID 13568. I thought I would be a good day to write about it. To understand the event Id first we have to understand about the Journal Wrap Entries I STROGLY RECOMMEND you to read this http://blogs.technet.com/b/instan/archive/2009/07/14/what-happens-in-a-journal-wrap.aspx.
According to the event ID:13568, it indicates that there is a domain controller is in a journal wrap state that the reason above I indicated to read the blog entry.
To troubleshoot the cause of a journal wrap, see the following article in the Microsoft Knowledge Base:292438 Troubleshooting Journal_Wrap Errors on Sysvol and DFS Replica Sets
After you determine the cause of a journal wrap or after you have taken steps to prevent future journal wraps, at a convenient time,make the following changes to the registry:
1. Stop FRS.
2. Start Registry Editor (Regedt32.exe).
3. Locate and click the following key in the registry:
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\NtFrs\Parameters\Backup/Restore/Process
at Startup
4. On the Edit menu, click Add Value , and then add the following registry value:
Value name: BurFlags
Data type: REG_DWORD
Radix: Hexadecimal
Value data: D2
5. Quit Registry Editor.
6. Restart FRS.
Last night I was Deploying Exchange 2010 at one of my customers end and when ever I was trying to prepare the active directory using the command setup /PrepareAD I was stopped with an error .

Resolution:
- Run Ldp.exe, expand Configuration, expand Services, and then double-click Microsoft Exchange.
- Right-click Microsoft Exchange and select Modify.
- Type otherWellknownObjects in the Edit Entry Attribute text box.
- Select the Delete option button.
- In the Ldp.exe results pane, find otherWellknownObjects.
Copy the entry, paste the entry into the Values text box of the Modify dialog box, and then press ENTER.


Note:
Make sure that you do not leave the Values field and Entry List blank, because this will delete all entries in the otherWellKnownObjects attribute, potentially including values that you did not want to delete. Finally, to execute the command, click Run.