CRM 2011 System.NullReferenceException error occurs while trying to save an entity

I had the situation where by i kept getting an error whilst trying to save an entity. This error message file typically contained some of the following:

Unhandled Exception: System.ServiceModel.FaultException`1[[Microsoft.Xrm.Sdk.OrganizationServiceFault, Microsoft.Xrm.Sdk, Version=5.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35]]: System.NullReferenceException: Microsoft Dynamics CRM has experienced an error. Reference number for administrators or support: #2DBD7965Detail:

-2147220970

System.NullReferenceException: Microsoft Dynamics CRM has experienced an error. Reference number for administrators or support: #2DBD7965
2011-03-04T08:30:14.1912773Z






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I think this has to do with the default Microsoft.Crm.Extensibility plugins thats added to each org...it seems inside there, it references some of the steps you create in your custom plugin/workflow such that when you delete/remove your plugin, its still got traces to it and then you cant save records. i found this out by trying to delete my custom entity( which failed), so i had to deactivate the Microsoft.Crm.Extensibility steps first,then i could delete my entity.