I am in the same boat, except I am stuck at v1.40.
I don't know anything about DVRupdate. But I did a quick check of the ASUS forums and another person with the same problem was told that it was because their drive was an OEM model instead of Retail.
I've never heard of this making a difference beyond the packaging. But as it happens, my drive is an OEM model as well. So, I guess they could have done something in the firmware that keeps their updater from working on it.
Anyone have any ideas?