The "The system cannot locate the resource specified" error occurs during ZyIMPORT stage in ZySCAN.
The 'Pdf Images' Import filter in ZySCAN is used and the 'Add filename field' option in the enabled.
The format of the imported PDF file(s) is not supported by the 'Pdf Images' Import filter in ZySCAN.
Prefer using the 'Pdf' ZySCAN import filter instead. Within the 'Pdf' ZySCAN Import filter options, you can choose whether to OCR or not the document. In both cases the 'Add filename field' option is available to automatically store the PDF original filename into the "PDFfilename" index field.