A log could prove useful.
Until then, your firmware is older than my granny. Current version is 1.29 and can be found here:
http://forum.rpc1.org/dl_firmware.php?download_id=2220
Also put the disc that your standalone claims is blank, but that Imgburn verified back in your burner and fire up Imgburn in Read or Write mode and copy/paste all the information contained there in this thread.