Rendering crashes on h.264

Hello everybody,

I have a problemm with kdenliv rendering my video. At the end you will find the report kdenlive gives me when it crashes.
I render with the "H.264" profile, the only thing I changed was the audio codec from "acc" to "libmp3lame".
So the thing is that kdenlive renders parts of my project fine. Just when I try to render more than 3 minutes of my video it crashes with an error and gives me a corrupted mp4 file. Shorter parts were rendered fine with no error or anything like that.

Here the profile:

f=mp4 hq=1 acodec=libmp3lame ab=%audiobitrate+'k' ar=48000 pix_fmt=yuv420p vcodec=libx264 minrate=0 vb=%bitrate+'k' g=250 bf=3 b_strategy=1 subcmp=2 cmp=2 coder=1 flags=+loop flags2=dct8x8 qmax=51 subq=7 qmin=10 qcomp=0.6 qdiff=4 trellis=1 aspect=%dar pass=%passes

I am not entirely sure wether I have installed all required libraries. I have some problems finding all of them for Kubuntu, but since it renders shorter parts of the project I assumed the source of the problem elsewhere.
I have tried some of the advices given in some other posts or in the bug reports but nothing helped(e.g. changing 0.6 to 0,6).

specifications:
Kubuntu 12.04
ffmpeg: 4:0.8.1-0ubuntu1
kdenlive: 0.9.2-0ubuntu0
libx264-120: 2:0.120.2151

locale:
LANG=de_DE.UTF-8
LANGUAGE=
LC_CTYPE="de_DE.UTF-8"
LC_NUMERIC="de_DE.UTF-8"
LC_TIME="de_DE.UTF-8"
LC_COLLATE="de_DE.UTF-8"
LC_MONETARY="de_DE.UTF-8"
LC_MESSAGES="de_DE.UTF-8"
LC_PAPER="de_DE.UTF-8"
LC_NAME="de_DE.UTF-8"
LC_ADDRESS="de_DE.UTF-8"
LC_TELEPHONE="de_DE.UTF-8"
LC_MEASUREMENT="de_DE.UTF-8"
LC_IDENTIFICATION="de_DE.UTF-8"
LC_ALL=

error report:

[mp3 @ 0x9763a0] max_analyze_duration reached
[mp3 @ 0x97cee0] max_analyze_duration reached
[mp3 @ 0x9a6ee0] max_analyze_duration reached
[mp3 @ 0x9aa820] max_analyze_duration reached
[matroska,webm @ 0x980b20] Estimating duration from bitrate, this may be inaccurate
[matroska,webm @ 0xc72700] Estimating duration from bitrate, this may be inaccurate
[matroska,webm @ 0xc42620] Estimating duration from bitrate, this may be inaccurate
[mp3 @ 0xa5b6e0] max_analyze_duration reached
[mp3 @ 0xa5b6e0] Estimating duration from bitrate, this may be inaccurate
[mp3 @ 0xa6e320] max_analyze_duration reached
[mp3 @ 0xa6e320] Estimating duration from bitrate, this may be inaccurate
[matroska,webm @ 0xdbb4c0] Estimating duration from bitrate, this may be inaccurate
[matroska,webm @ 0x2ca5ea0] Estimating duration from bitrate, this may be inaccurate
[matroska,webm @ 0x2b94d80] Estimating duration from bitrate, this may be inaccurate
[matroska,webm @ 0x1196700] Estimating duration from bitrate, this may be inaccurate
[matroska,webm @ 0x2e43140] Estimating duration from bitrate, this may be inaccurate
[matroska,webm @ 0x2f39fe0] Estimating duration from bitrate, this may be inaccurate
[mp3 @ 0x2f28160] max_analyze_duration reached
[mp3 @ 0x2f28820] max_analyze_duration reached
[matroska,webm @ 0x7c413c0] Estimating duration from bitrate, this may be inaccurate
[matroska,webm @ 0xa8a50a0] Estimating duration from bitrate, this may be inaccurate
[matroska,webm @ 0x6ddc440] Estimating duration from bitrate, this may be inaccurate
[matroska,webm @ 0x702d8e0] Estimating duration from bitrate, this may be inaccurate
[matroska,webm @ 0xb8e3100] Estimating duration from bitrate, this may be inaccurate
[matroska,webm @ 0x70683a0] Estimating duration from bitrate, this may be inaccurate
[matroska,webm @ 0x70656c0] Estimating duration from bitrate, this may be inaccurate
[matroska,webm @ 0xbd60b40] Estimating duration from bitrate, this may be inaccurate
[matroska,webm @ 0xbe585e0] Estimating duration from bitrate, this may be inaccurate
[mpegts @ 0x7066100] max_analyze_duration reached
[mpegts @ 0xb9c5f00] max_analyze_duration reached
[mpegts @ 0xa952440] max_analyze_duration reached
[mpegts @ 0xbde9080] max_analyze_duration reached
[mpegts @ 0xbe59f60] max_analyze_duration reached
[mpegts @ 0xbd9fa40] max_analyze_duration reached
[mpegts @ 0xb9b3c80] max_analyze_duration reached
[mpegts @ 0xb9d4100] max_analyze_duration reached
[mp3 @ 0x7ff7f40037c0] max_analyze_duration reached
[mp3 @ 0x7ff7f4009900] max_analyze_duration reached
[libx264 @ 0x7ff7fc2c8e80] [Eval @ 0x7ff81794a490] Invalid chars '.6' at the end of expression '0.6' [libx264 @ 0x7ff7fc2c8e80] Unable to parse option value "0.6"

Hope someone can help me.