From a newsgroup post: "This event can occur if you backup a GPO which contains custom registry security settings, and the Owner for this registry key they were trying to set security on, had been set to one of their own admins. You may edit the policy to change the owner to be “Administrators” group (the default) as following:
1. Right click the policy in Group Policy Management and select Edit.
2. In Group Policy Object Editor, right click the Default Domain Policy and
select Properties.
3. In Security tab, click Advanced.
4. In Advanced Security Settings for page, confirm the Owner is “Administrators” in Owner tab.
If the problem still persists, please enable verbose logging of the Group Policy Management Console by adding the following registry keys:
Key: HKLM\Software\Microsoft\Windows NT\CurrentVersion\Diagnostics
Value: GPMgmtTraceLevel
Value Type: REG_DWORD
Value Data: 2
Key: HKLM\Software\Microsoft\Windows NT\CurrentVersion\Diagnostics
Value: GPMgmtLogFileOnly
Value Type: REG_DWORD
Value Data: 1
This creates a gpmgmt.log that is located in %temp%. The temp folder is in the profile of the currently logged on user".