You have selected a Bar Type which does not allow the Hooks used by the current shape. Please select a different Shape / Bar Type combination, or change the Hook permissions for the desired Bar Type (see Hook Lengths under Rebar Bar properties). 
   Namespace:   Autodesk.Revit.DB  
  Assembly:   RevitAPI  (in RevitAPI.dll) Version: 2015.0.0.0 (2015.0.0.0) 
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