[itsme]

Strange. There's something invisible in column "PDFLastPage" that prevents ISBLANK to return TRUE. A simple delete of the cells in PDFLastPage doesn't help. If I enter something (any character works) and delete it again, the cell is empty and the hyphen disappears.
It might have something to do with the way you created the XLS or with the way you edited the export file. I use Notepad++ instead of Wordpad. You could try that. If that doesn't help we need to check your workflow step by step.