Just to say that I have discovered that the error "failed to start scanner: Invalid argument" and the message in the kernel log "bayard kernel: usb 3-1: usbfs: USBDEVFS_CONTROL failed cmd xsane rqt 64 rq 1 len 64 ret -110" seem to have been caused by not having the external power supply to the Belkin usb2.0 cardbus card plugged in. I'm still only getting an image of half a page, though.
