Converting an custom entity from organization owned to user owned in CRM 2011

I have been struggling to convert an custom entity in CRM 2011 from Organization owned to User owned, I followed the instructions on this blog(http://dynamics2011.blogspot.com/2012/04/crm-2011-changing-entity-from.html) but when I re-import the solution i get this error "object reference is not set to an instance of an object". I managed to delete relationships associated with the entity but getting an error when I attempt to delete the managed relationship associated to it, below is the screen-shot and a log file of the error I have encountered . Your assistance will be highly appreciated. Nyiko Maluleke

Unhandled Exception: System.ServiceModel.FaultException`1[[Microsoft.Xrm.Sdk.OrganizationServiceFault, Microsoft.Xrm.Sdk, Version=5.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35]]: System.Web.HttpUnhandledException: Microsoft Dynamics CRM has experienced an error. Reference number for administrators or support: #CB7F872EDetail: 
<OrganizationServiceFault xmlns:i="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://schemas.microsoft.com/xrm/2011/Contracts">
  <ErrorCode>-2147220970</ErrorCode>
  <ErrorDetails xmlns:d2p1="http://schemas.datacontract.org/2004/07/System.Collections.Generic">
    <KeyValuePairOfstringanyType>
      <d2p1:key>CallStack</d2p1:key>
      <d2p1:value xmlns:d4p1="http://www.w3.org/2001/XMLSchema" i:type="d4p1:string">   at System.Web.UI.Page.HandleError(Exception e)
   at System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint)
   at System.Web.UI.Page.ProcessRequest(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint)
   at System.Web.UI.Page.ProcessRequest()
   at System.Web.UI.Page.ProcessRequest(HttpContext context)
   at System.Web.HttpApplication.CallHandlerExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute()
   at System.Web.HttpApplication.ExecuteStep(IExecutionStep step, Boolean&amp; completedSynchronously)</d2p1:value>
    </KeyValuePairOfstringanyType>
  </ErrorDetails>
  <Message>System.Web.HttpUnhandledException: Microsoft Dynamics CRM has experienced an error. Reference number for administrators or support: #CB7F872E</Message>
  <Timestamp>2012-06-12T06:45:05.1805091Z</Timestamp>
  <InnerFault>
    <ErrorCode>-2147160014</ErrorCode>
    <ErrorDetails xmlns:d3p1="http://schemas.datacontract.org/2004/07/System.Collections.Generic">
      <KeyValuePairOfstringanyType>
        <d3p1:key>CallStack</d3p1:key>
        <d3p1:value xmlns:d5p1="http://www.w3.org/2001/XMLSchema" i:type="d5p1:string">   at Microsoft.Crm.Dialogs.DeleteDialogPage.ProcessCrmException(CrmException crmEx)
   at Microsoft.Crm.Dialogs.DeleteDialogPage.ConfigureForm()
   at Microsoft.Crm.Application.Controls.AppUIPage.OnPreRender(EventArgs e)
   at System.Web.UI.Control.PreRenderRecursiveInternal()
   at System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint)</d3p1:value>
      </KeyValuePairOfstringanyType>
    </ErrorDetails>
    <Message>The 'Delete' operation on the current component(name='EntityRelationshipRole', id='ceac1baf-2b7e-e111-a7d6-e4115bdd58bd') failed during managed property evaluation of condition: 'Microsoft.Crm.BusinessEntities.IsComponentDeletionEnabledCondition'</Message>
    <Timestamp>2012-06-12T06:45:05.1814856Z</Timestamp>
    <InnerFault i:nil="true" />
    <TraceText i:nil="true" />
  </InnerFault>
  <TraceText i:nil="true" />
</OrganizationServiceFault>