i changed to Ubuntu 12.04 some weeks ago. I have more problems with rendering projects then ever. No rendering comes over 50%. Every time Errors of mp3 or missed frames. I thought it is temperature and dissembled my laptop, cleaned air pipes, fan and did fresh heat-contact-paste at the Grafic-Chip and CPU and got temperature down from 90 (average) to 65(maximum) °C. Problem still exist --> No thermal-problem.
I updated the software like described to PPT and added all the packages like mlt and so on. Tried after new updates again and again. Didn´t work.
If I start OpenShot from Commandline, with

root@abcde:~# openshot /media/Path/folder/Part2.osp 

i get this output:

------------------------- ERROR 1 ------------------------------
Failed to import 'from openshot import main'
Error Message: cannot import name main
----------------------------------------------------------------
--------------------------------
   OpenShot (version 1.4.2)
--------------------------------
Process no longer exists: 14051.  Creating new pid lock file.
Adding files to the watch queue:
No LADSPA plugins were found!

Check your LADSPA_PATH environment variable.

Detecting formats, codecs, and filters...
---
video_codecs:
  - a64multi
  - a64multi5
<<many codecs>>
audio codecs
<<many codecs>>
formats
<<many formats>>
...
GenerateXML for an Effect
GenerateXML for an Effect
GenerateXML for an Effect
GenerateXML for an Effect
GenerateXML for an Effect
GenerateXML for an Effect
GenerateXML for an Effect
GenerateXML for an Effect
GenerateXML for an Effect
[mp3 @ 0xbfaabe0] max_analyze_duration reached
[mp3 @ 0xbfe93a0] max_analyze_duration reached
[mp3 @ 0xbfccfa0] max_analyze_duration reached
[mp3 @ 0xbfe92c0] max_analyze_duration reached
[mp3 @ 0xc019480] max_analyze_duration reached
[mp3 @ 0xc04c020] max_analyze_duration reached
[mp3 @ 0xc041360] max_analyze_duration reached
[mp3 @ 0xc07b580] max_analyze_duration reached
[mp3 @ 0xbfd8960] max_analyze_duration reached
[mp3 @ 0xc0aa620] max_analyze_duration reached
[mp3 @ 0xc0a44e0] max_analyze_duration reached
[mp3 @ 0xc0d9760] max_analyze_duration reached
project state modified
state saved
[mp3 @ 0xa8a88580] max_analyze_duration reached
[mp3 @ 0x90abe600] max_analyze_duration reached
NEW SDL CONSUMER
[mp3 @ 0xd966a60] max_analyze_duration reached
[mp3 @ 0xd9a53e0] max_analyze_duration reached
[mp3 @ 0xd998b80] max_analyze_duration reached
[mp3 @ 0xd9d89a0] max_analyze_duration reached
[mp3 @ 0xd9ce040] max_analyze_duration reached
[mp3 @ 0xda07d00] max_analyze_duration reached
[mp3 @ 0xd9d4440] max_analyze_duration reached
[mp3 @ 0xda36f00] max_analyze_duration reached
[mp3 @ 0xda33d20] max_analyze_duration reached
[mp3 @ 0xda66040] max_analyze_duration reached
[mp3 @ 0xd971260] max_analyze_duration reached
[mp3 @ 0xda952e0] max_analyze_duration reached
[mp3 @ 0xa8a8cc00] max_analyze_duration reached
[mp3 @ 0xa8a60e80] max_analyze_duration reached

Then i try to render the clip for WEB-VIMEOHD-25fps-medium
Output:

on_tlbMakeMovie_clicked called with self.GtkToolButton
on_cboExportType_changed
on_cboUploadServices_changed
on_cboProjectType_changed
on_cboExportTo_changed
on_btnExportVideo_clicked
NEW SDL CONSUMER
GenerateXML for an Effect
GenerateXML for an Effect
GenerateXML for an Effect
GenerateXML for an Effect
GenerateXML for an Effect
GenerateXML for an Effect
GenerateXML for an Effect
GenerateXML for an Effect
GenerateXML for an Effect
[mp3 @ 0x1aa5ba40] max_analyze_duration reached
[mp3 @ 0x1aa63aa0] max_analyze_duration reached
[mp3 @ 0x1aa78320] max_analyze_duration reached
[mp3 @ 0x1aacd980] max_analyze_duration reached
[mp3 @ 0x1aa97060] max_analyze_duration reached
[mp3 @ 0x1aafcc20] max_analyze_duration reached
[mp3 @ 0x1aaf66a0] max_analyze_duration reached
[mp3 @ 0x1aaf0b60] max_analyze_duration reached
[mp3 @ 0x1ab1f8a0] max_analyze_duration reached
[mp3 @ 0x1aae9ea0] max_analyze_duration reached
[mp3 @ 0x1ab29940] max_analyze_duration reached
[mp3 @ 0x1ab8a260] max_analyze_duration reached
[mp3 @ 0xd879100] max_analyze_duration reached
[mp3 @ 0xd8c4440] max_analyze_duration reached

[mp3 @ 0xc5db1a0] max_analyze_duration reached
[mp3 @ 0xcd10080] max_analyze_duration reached
[mp3 @ 0xcc2af40] max_analyze_duration reached
[mp3 @ 0xd6fba80] max_analyze_duration reached
[mp3 @ 0xd6ca000] max_analyze_duration reached
[mp3 @ 0xd8f2260] max_analyze_duration reached
[mp3 @ 0xd8ddee0] max_analyze_duration reached
[mp3 @ 0xc66e500] max_analyze_duration reached
sys:1: GtkWarning: gdk_pixbuf_get_has_alpha: assertion `GDK_IS_PIXBUF (pixbuf)' failed
sys:1: GtkWarning: gdk_pixbuf_get_rowstride: assertion `GDK_IS_PIXBUF (pixbuf)' failed
sys:1: GtkWarning: gdk_pixbuf_get_pixels: assertion `GDK_IS_PIXBUF (pixbuf)' failed
Speicherzugriffsfehler (Speicherabzug geschrieben)

I use clips from a "GoproWide Rev1" and "CANON SX30IS"
and Render it on a HP HDX 18
and Ubuntu 12.04
Kernel Linux 3.2.0-26-generic-pae
GNOME 3.4.1
Memory 7.9GB
Prozessor Intel® Core™2 Quad CPU Q9000 @ 2.00GHz × 4 



DEBUG-OUTPUT

root@gaensebluemchen:~/Downloads# python debug.py 
-----------------------------------------------------------
OpenShot Debug File 0.0.2 - 2012-07-19 23:06:26.186354
-----------------------------------------------------------
This file contains a list of installed packages related to OpenShot,
locations of files, and a list of shared libraries used by python-mlt.


-----------------------------------------------------------
Distribution Version Info
-----------------------------------------------------------
LSB Version:	core-2.0-ia32:core-2.0-noarch:core-3.0-ia32:core-3.0-noarch:core-3.1-ia32:core-3.1-noarch:core-3.2-ia32:core-3.2-noarch:core-4.0-ia32:core-4.0-noarch
Distributor ID:	Ubuntu
Description:	Ubuntu 12.04 LTS
Release:	12.04
Codename:	precise



-----------------------------------------------------------
List of Installed Packages
-----------------------------------------------------------
Gewünscht=Unbekannt/Installieren/R=Entfernen/P=Vollständig Löschen/Halten
| Status=Nicht/Installiert/Config/U=Entpackt/halb konFiguriert/
         Halb installiert/Trigger erWartet/Trigger anhängig
|/ Fehler?=(kein)/R=Neuinstallation notwendig (Status, Fehler: GROSS=schlecht)
||/ Name                                          Version                                 Beschreibung
+++-=============================================-=======================================-==============================================================================
un  libmlt1                                       <keine>                                 (keine Beschreibung vorhanden)
un  libmlt2                                       <keine>                                 (keine Beschreibung vorhanden)
ii  openshot                                      1.4.2-1                                 Create and edit videos and movies
un  python-mlt                                    <keine>                                 (keine Beschreibung vorhanden)
un  python-mlt2                                   <keine>                                 (keine Beschreibung vorhanden)
Kein Paket gefunden, das auf openshot-mlt passt.



-----------------------------------------------------------
Python Path (i.e. sys.path)
-----------------------------------------------------------
/home/bernibaerchen/Downloads
/usr/lib/python2.7
/usr/lib/python2.7/plat-linux2
/usr/lib/python2.7/lib-tk
/usr/lib/python2.7/lib-old
/usr/lib/python2.7/lib-dynload
/usr/local/lib/python2.7/dist-packages
/usr/lib/python2.7/dist-packages
/usr/lib/python2.7/dist-packages/PIL
/usr/lib/python2.7/dist-packages/gst-0.10
/usr/lib/python2.7/dist-packages/gtk-2.0
/usr/lib/pymodules/python2.7
/usr/lib/python2.7/dist-packages/ubuntu-sso-client
/usr/lib/python2.7/dist-packages/ubuntuone-client
/usr/lib/python2.7/dist-packages/ubuntuone-control-panel
/usr/lib/python2.7/dist-packages/ubuntuone-couch
/usr/lib/python2.7/dist-packages/ubuntuone-installer
/usr/lib/python2.7/dist-packages/ubuntuone-storage-protocol
/usr/lib/python2.7/dist-packages/wx-2.6-gtk2-unicode


-----------------------------------------------------------
WARNING: /usr/lib/pymodules/python2.6 missing from Python Path
-----------------------------------------------------------
This folder is where the python-mlt bindings are stored.  If this folder
is not in the Python Path, it will not find the 'mlt' module.


-----------------------------------------------------------
Files in /usr/lib/pymodules/python2.6/mlt (used by python-mlt)
-----------------------------------------------------------
find: "/usr/lib/pymodules/python2.6/mlt": Datei oder Verzeichnis nicht gefunden



-----------------------------------------------------------
Attempt to import mlt (using Python)
-----------------------------------------------------------
Successfully imported mlt library!



I saw that libmlt4 and python-mlt3 is installed.
What can i do more? Is there more information i can give you to help me?
thanks a lot for your time. There are abeout 400 Kids looking forward for a nice Summer-Camp-Movie.

Looking forward
bernibaerchen