I experienced the same problem for certain formats.
I installed Openshot via PPA on Ubuntu 9.10 64bit.

Examples of when it crashed:

***** Export to MPG4, medium quality

Added /usr/share/openshot to system path
--------------------------------
   OpenShot (version 1.0.0)
--------------------------------
/usr/share/openshot/windows/SimpleGladeApp.py:340: GtkWarning: gtk_toolbar_set_icon_size: assertion `icon_size != GTK_ICON_SIZE_INVALID' failed
  return gtk.glade.XML(self.glade_path, root, domain)
A new frmMain has been created
on_mnuMakeMovie1_activate called with self.mnuMakeMovie
on_tlbMakeMovie_clicked called with self.mnuMakeMovie
on_cboProjectType_changed
on_cboExportTo_changed
on_btnExportVideo_clicked
consumer_avformat.c: audio codec libmp3lame unrecognised - ignoring
consumer_avformat.c: Unable to encode audio - disabling audio output.
[mp4 @ 0x18b3710]track 1: codec frame size is not set
Floating point exception


***** Export to Vimeo HD, HDV720 30p, high quality

Added /usr/share/openshot to system path
--------------------------------
   OpenShot (version 1.0.0)
--------------------------------
/usr/share/openshot/windows/SimpleGladeApp.py:340: GtkWarning: gtk_toolbar_set_icon_size: assertion `icon_size != GTK_ICON_SIZE_INVALID' failed
  return gtk.glade.XML(self.glade_path, root, domain)
A new frmMain has been created
on_mnuMakeMovie1_activate called with self.mnuMakeMovie
on_tlbMakeMovie_clicked called with self.mnuMakeMovie
on_cboProjectType_changed
on_cboExportTo_changed
on_cboProjectType_changed
on_btnExportVideo_clicked
consumer_avformat.c: audio codec libfaac unrecognised - ignoring
consumer_avformat.c: video codec libx264 unrecognised - ignoring
consumer_avformat.c: Unable to encode audio - disabling audio output.
[mov @ 0x1e4d5f0]track 1: codec frame size is not set
Floating point exception


***** Export to iPod, square, high quality

Added /usr/share/openshot to system path
--------------------------------
   OpenShot (version 1.0.0)
--------------------------------
/usr/share/openshot/windows/SimpleGladeApp.py:340: GtkWarning: gtk_toolbar_set_icon_size: assertion `icon_size != GTK_ICON_SIZE_INVALID' failed
  return gtk.glade.XML(self.glade_path, root, domain)
A new frmMain has been created
on_frmMain_key_press_event
on_frmMain_key_press_event
on_mnuMakeMovie1_activate called with self.mnuMakeMovie
on_tlbMakeMovie_clicked called with self.mnuMakeMovie
on_cboProjectType_changed
on_cboExportTo_changed
on_cboProjectType_changed
on_btnExportVideo_clicked
on_cboProjectType_changed
on_cboProjectType_changed
on_btnExportVideo_clicked
consumer_avformat.c: audio codec libfaac unrecognised - ignoring
consumer_avformat.c: video codec libx264 unrecognised - ignoring
consumer_avformat.c: Unable to encode audio - disabling audio output.
[ipod @ 0x369f550]track 1: codec frame size is not set
Segmentation fault


***** After installing/uninstalling the following:
libavcodec52 will be removed
libavformat52 will be removed
libavutil49 will be removed
libavcodec-extra-52 (version 4:0.5+svn20090706-2ubuntu3) will be installed
libavformat-extra-52 (version 4:0.5+svn20090706-2ubuntu3) will be installed
libavutil-extra-49 (version 4:0.5+svn20090706-2ubuntu3) will be installed
libopenjpeg2 (version 1.3+dfsg-4) will be installed


*** All MP4-exports seems to work
However, still not Vimeo HD or iPod, for instance:

Added /usr/share/openshot to system path
--------------------------------
   OpenShot (version 1.0.0)
--------------------------------
/usr/share/openshot/windows/SimpleGladeApp.py:340: GtkWarning: gtk_toolbar_set_icon_size: assertion `icon_size != GTK_ICON_SIZE_INVALID' failed
  return gtk.glade.XML(self.glade_path, root, domain)
A new frmMain has been created
on_frmMain_key_press_event
on_frmMain_key_press_event
on_mnuMakeMovie1_activate called with self.mnuMakeMovie
on_tlbMakeMovie_clicked called with self.mnuMakeMovie
on_cboProjectType_changed
on_cboExportTo_changed
on_cboProjectType_changed
on_btnExportVideo_clicked
consumer_avformat.c: audio codec libfaac unrecognised - ignoring
consumer_avformat.c: Unable to encode audio - disabling audio output.
[mov @ 0x411b310]track 1: codec frame size is not set
Floating point exception







Added /usr/share/openshot to system path
--------------------------------
   OpenShot (version 1.0.0)
--------------------------------
/usr/share/openshot/windows/SimpleGladeApp.py:340: GtkWarning: gtk_toolbar_set_icon_size: assertion `icon_size != GTK_ICON_SIZE_INVALID' failed
  return gtk.glade.XML(self.glade_path, root, domain)
A new frmMain has been created
on_mnuMakeMovie1_activate called with self.mnuMakeMovie
on_tlbMakeMovie_clicked called with self.mnuMakeMovie
on_cboProjectType_changed
on_cboExportTo_changed
on_btnExportVideo_clicked
on_cboProjectType_changed
on_btnExportVideo_clicked
consumer_avformat.c: audio codec libfaac unrecognised - ignoring
consumer_avformat.c: Unable to encode audio - disabling audio output.
[ipod @ 0x160d980]track 1: codec frame size is not set
Floating point exception