Unfortunately, this, along with all the other PDF-to-whatever converters, cannot handle PDF's that have been rasterized; i.e., they must have the text still intact. Your only real option with this type of PDF is to run OCR and hope for the best.
BTW I tried Zamzar and a couple others on some PDF's I have a little while back, best bet is to find a tool that makes the PDF work for your device. Thanks for the resource, I'm sure many can still benefit from it!
