I dragged 'gridflow' to /Library/Pd folder.
and then.,

/Library/Pd/gridflow/gridflow.pd_darwin: dlopen(/Library/Pd/gridflow/gridflow.pd_darwin, 10): Symbol not found: __ZN11imageStruct5clearEv
  Referenced from: /Library/Pd/gridflow/gridflow.pd_darwin
  Expected in: flat namespace

/Library/Pd/gridflow: can't load library


any idea?