Falha ao abrir o objeto de diretiva de grupo -Windows 7 Administrator

Sempre que tento acessar o Editor de Diretiva de Grupo Local (ou acessar a Política de segurança local na pasta Ferramentas Administrativas), recebo a seguinte mensagem:

"Falha ao abrir o Objeto de Diretiva de Grupo neste computador. Talvez você não tenha os direitos apropriados.

Detalhes: Erro não especificado "

Por favor, alguém pode sugerir qual poderia ser o problema?

Eu usei um limpador de registro, que poderia ter causado o dano.

Detalhes

Estou usando o Windows 7 Professional como administrador. O PC é independente - sem controlador de domínio.

Olhou no log de eventos administrativos e encontrou muitos destes:

Log Name:      System
Source:        Microsoft-Windows-GroupPolicy
Date:          28/05/2011 23:43:08
Event ID:      1096
Task Category: None
Level:         Error
Keywords:      
User:          Study\The Administrator
Computer:      Study
Description:
The processing of Group Policy failed. Windows could not apply the registry-based policy settings for the Group Policy object LocalGPO. Group Policy settings will not be resolved until this event is resolved. View the event details for more information on the file name and path that caused the failure.
Event Xml:
<Event xmlns="http://schemas.microsoft.com/win/2004/08/events/event">
  <System>
    <Provider Name="Microsoft-Windows-GroupPolicy" Guid="{AEA1B4FA-97D1-45F2-A64C-4D69FFFD92C9}" />
    <EventID>1096</EventID>
    <Version>0</Version>
    <Level>2</Level>
    <Task>0</Task>
    <Opcode>1</Opcode>
    <Keywords>0x8000000000000000</Keywords>
    <TimeCreated SystemTime="2011-05-28T22:43:08.750000000Z" />
    <EventRecordID>8415697</EventRecordID>
    <Correlation ActivityID="{2B1F7048-0A0F-4367-AF18-DAA5F16B73A6}" />
    <Execution ProcessID="728" ThreadID="3040" />
    <Channel>System</Channel>
    <Computer>Study</Computer>
    <Security UserID="S-1-5-21-2954353469-387026828-152714653-1014" />
  </System>
  <EventData>
    <Data Name="SupportInfo1">2</Data>
    <Data Name="SupportInfo2">1232</Data>
    <Data Name="ProcessingMode">2</Data>
    <Data Name="ProcessingTimeInMilliseconds">390</Data>
    <Data Name="ErrorCode">13</Data>
    <Data Name="ErrorDescription">The data is invalid. </Data>
    <Data Name="DCName">
    </Data>
    <Data Name="GPOCNName">LocalGPO</Data>
    <Data Name="FilePath">C:\Windows\System32\GroupPolicy\User\registry.pol</Data>
  </EventData>
</Event>

Também encontrei cargas destes, mas não sei se isso é relevante:

Log Name:      System
Source:        Microsoft-Windows-DistributedCOM
Date:          28/05/2011 23:37:36
Event ID:      10016
Task Category: None
Level:         Error
Keywords:      Classic
User:          NETWORK SERVICE
Computer:      Study
Description:
The application-specific permission settings do not grant Local Activation permission for the COM Server application with CLSID 
{BC866CF2-5486-41F7-B46B-9AA49CF3EBB1}
 and APPID 
{066FCC09-2096-4EEF-AA2F-353DB80F1BF8}
 to the user NT AUTHORITY\NETWORK SERVICE SID (S-1-5-20) from address LocalHost (Using LRPC). This security permission can be modified using the Component Services administrative tool.
Event Xml:
<Event xmlns="http://schemas.microsoft.com/win/2004/08/events/event">
  <System>
    <Provider Name="Microsoft-Windows-DistributedCOM" Guid="{1B562E86-B7AA-4131-BADC-B6F3A001407E}" EventSourceName="DCOM" />
    <EventID Qualifiers="49152">10016</EventID>
    <Version>0</Version>
    <Level>2</Level>
    <Task>0</Task>
    <Opcode>0</Opcode>
    <Keywords>0x80000000000000</Keywords>
    <TimeCreated SystemTime="2011-05-28T22:37:36.000000000Z" />
    <EventRecordID>8415679</EventRecordID>
    <Correlation />
    <Execution ProcessID="0" ThreadID="0" />
    <Channel>System</Channel>
    <Computer>Study</Computer>
    <Security UserID="S-1-5-20" />
  </System>
  <EventData>
    <Data Name="param1">application-specific</Data>
    <Data Name="param2">Local</Data>
    <Data Name="param3">Activation</Data>
    <Data Name="param4">{BC866CF2-5486-41F7-B46B-9AA49CF3EBB1}</Data>
    <Data Name="param5">{066FCC09-2096-4EEF-AA2F-353DB80F1BF8}</Data>
    <Data Name="param6">NT AUTHORITY</Data>
    <Data Name="param7">NETWORK SERVICE</Data>
    <Data Name="param8">S-1-5-20</Data>
    <Data Name="param9">LocalHost (Using LRPC)</Data>
  </EventData>
</Event>

Eu apaguei o arquivo .pol do GPO da máquina em c: \ windows \ system32 \ GroupPolicy \ Machine

Eu tive que mostrar arquivos e pastas ocultos primeiro.

Eu reiniciei e recriou uma nova política local. Agora, as políticas de GPO de domínio são aplicadas sem falhas.