Same thing here:
My hardware/software config is as follows: an Asus P6T with a Core i7 920 (D0 stepping but not overclocked), 12Gb Corsair DDR3, RAID 0 drives with a few hundred Gig of space, Windows 7 Pro 64 bit build 7600, AVSVC 6.4.3.419, AnyDVD HD 6.6.4.2. All software is legit and registered.
I have ripped my BDs to the desktop using AnyDVD then mounted the image to Virtual Clone Drive. With the rips, I have tried "Keep protection" mode and unchecking protected mode in AnyDVD.
I am trying to convert to MKV. The AVSVC program indicates an approximate 7 hour conversion, then quits about 5 hours into the conversion, at around 82%. The settings I am using are Preset "HD Video 1080p", but with the bitrate reduces from 9000 to 4500 to keep the end file size down to something reasonable.