Using MultiAVCHD4.1 I get avs4x264.exe has stopped working

[Onceler2]

here is what media nfo is saying:
Format : BDAV
Format/Info : Blu-ray Video
File size : 8.57 GiB
Duration : 58mn 32s
Overall bit rate mode : Variable
Overall bit rate : 21.0 Mbps
Maximum Overall bit rate : 35.5 Mbps

Video
ID : 4113 (0x1011)
Menu ID : 1 (0x1)
Format : AVC
Format/Info : Advanced Video Codec
Format profile : High@L4.1
Format settings, CABAC : Yes
Format settings, ReFrames : 3 frames
Codec ID : 27
Duration : 58mn 32s
Bit rate mode : Variable
Bit rate : 19.5 Mbps
Maximum bit rate : 36.0 Mbps
Width : 1 920 pixels
Height : 1 080 pixels
Display aspect ratio : 16:9
Frame rate : 23.976 fps
Standard : NTSC
Color space : YUV
Chroma subsampling : 4:2:0
Bit depth : 8 bits
Scan type : Progressive
Bits/(Pixel*Frame) : 0.392
Stream size : 7.97 GiB (93%)

Audio
ID : 4352 (0x1100)
Menu ID : 1 (0x1)
Format : AC-3
Format/Info : Audio Coding 3
Mode extension : CM (complete main)
Format settings, Endianness : Big
Codec ID : 129
Duration : 58mn 32s
Bit rate mode : Constant
Bit rate : 640 Kbps
Channel(s) : 6 channels
Channel positions : Front: L C R, Side: L R, LFE
Sampling rate : 48.0 KHz
Bit depth : 16 bits
Compression mode : Lossy
Stream size : 268 MiB (3%)

Text
ID : 4608 (0x1200)
Menu ID : 1 (0x1)
Format : PGS
Codec ID : 144
Language : English

I can't figure out the problem, I have tried both 32 and 64 bit mode but it makes no difference. I am trying to fit a lot of these onto one blu ray.

[Onceler2]

I am using 2 pass VHQ

[digicube]

Download latest fmss2. https://github.com/FFMS/ffms2/releases