I found this comment on the Pioneer-Website:
*We have found a problem for the firmware Version 1.18. Some of the drive users were unable to install the firmware at all.
If you have experienced the mentioned problem, please be kind to update your drive with the following firmware which is released on 10th December.
If you have installed the above firmware(Version 1.18, dated 8th December) without problem, your are not necessary to update your drive with this firmware at all. http://wwwbsc.pioneer.co.jp/product-e/ibs/device_e/dev00001r_e.html