[flexcoders] Property not found on mx.collections.ItemWrapper

[oneworld95]

Hi. I've added an effect to an AdvancedDataGrid,

<mx:AdvancedDataGrid dataChangeEffect="{DefaultTileListEffect}" ... >

and now it throws this error,

Property SelectedFileName not found on mx.collections.ItemWrapper and
there is no default value.

It's on a line in an itemRenderer's set data() method where it tries
to read the SelectedFileName. 

if (data.SelectedFileName != null && data.SelectedFileName !=
undefined && data.SelectedFileName != ""){
  loaded = true;
  fileName = data.SelectedFileName;
}

I've not been able to find anything on this error. Help! Thanks.