running an action on multiple open documents

Can you post your Action? I tried to replicate you problem by pasting in this web page into a document. Then delet  all other layer and mask your append. Save the document as a PSD. Then loaded the layer mask as a selection. So the document's  layer has a layer mask and an active selection. I then ran the Image Processor pro to catch your problem saving it as a PGN file. Image Processor Pro ran without a problem  and I pasted in the PGN file Image Processor Pro saved.  By chance are any of your Open documents new documents that have not been saved? If any are Image Processor and Image Processor Pro can not process new document that have not been saved. The Image Processor scripts only process one document at a time. It loops through the open Document ring to process all open documents. The documents will also remain open and not have ant effects made by you actions. Only the save files will have been touched by your actions..