Google translates the error message as “Failed to load the pdf document”. Since it seems to be streaming the document to adobe reader properly and since chrome is just failing to load the document but seems to be finding it, have you made sure the pdf viewer in chrome is working properly? have you tested in other browsers?
File f = new File(app.getApplication().getContext().getBaseDirectory().getPath() + "/relat.pdf");
FileResource fr = new FileResource(f, app.getApplication());