[jlink] DetailSymbolInstItem.GetInstructions throws XToolkitGeneralError

I've selected a BoM balloon from a drawing and when trying to retrieve (create) instructions on a symbol instance item, jlink always throws XToolkitGeneralError.

Is there any other way of retrieving the instructions for symbol instances.

Ex code:

DetailSymbolInstItem balloon = (DetailSymbolInstItem) drw.GetDetailItem(DetailType.DETAIL_SYM_INSTANCE, item.GetId());

balloon.GetInstructions(true);//throws error irrespective of the argument (true or false)

Can somebody please point me in the right direction.