quick campaign - Cannot specify owner on activity for distribution

Hey all,

if i create an quick campaign to send emails, i get the following error:

Unhandled Exception: System.ServiceModel.FaultException`1[[Microsoft.Xrm.Sdk.OrganizationServiceFault, Microsoft.Xrm.Sdk, Version=5.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35]]: Cannot specify owner on activity for distributionDetail:
<OrganizationServiceFault xmlns:i="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://schemas.microsoft.com/xrm/2011/Contracts">
  <ErrorCode>-2147220697</ErrorCode>
  <ErrorDetails xmlns:d2p1="http://schemas.datacontract.org/2004/07/System.Collections.Generic" />
  <Message>Cannot specify owner on activity for distribution</Message>
  <Timestamp>2013-02-18T14:15:58.0183591Z</Timestamp>
  <InnerFault>
    <ErrorCode>-2147220697</ErrorCode>
    <ErrorDetails xmlns:d3p1="http://schemas.datacontract.org/2004/07/System.Collections.Generic" />
    <Message>Cannot specify owner on activity for distribution</Message>
    <Timestamp>2013-02-18T14:15:58.0183591Z</Timestamp>
    <InnerFault i:nil="true" />
    <TraceText i:nil="true" />
  </InnerFault>
  <TraceText i:nil="true" />
</OrganizationServiceFault>
   at Microsoft.Crm.Extensibility.OrganizationSdkServiceInternal.Execute(OrganizationRequest request, CorrelationToken correlationToken, CallerOriginToken callerOriginToken, WebServiceType serviceType)
   at Microsoft.Crm.Extensibility.InprocessServiceProxy.ExecuteCore(OrganizationRequest request)
   at Microsoft.Crm.Asynchronous.ActivityPropagationOperation.ProcessEntityWithPaging(String entityLogicalName, QueryExpression& alreadyProcessed, AsyncEvent asyncEvent)
   at Microsoft.Crm.Asynchronous.ActivityPropagationOperation.InternalExecute(AsyncEvent asyncEvent)
   at Microsoft.Crm.Asynchronous.AsyncOperationCommand.Execute(AsyncEvent asyncEvent)
   at Microsoft.Crm.Asynchronous.PoolHandler.ProcessAsyncEvent(IGenericEventData eventData)

i dont know whats wrong. theres no problem with the async service and i always put in the right owner... theres no problem when i create a quick campaign for phone calls, appointsments, etc.

thanks for your help !