[Qgis-user] PyQGIS can't load - QGIS 1.7 loading error obtained after upgrade linux/ubuntu from distribution 11.04 to 11.10

[Florent Beck]

Hello,

I am using QGIS for a while and have being more or less lucky with bug
issues, but this time I don't understand alone how to fix it.
I was using QGIS 1.7 since its release under Linux/Ubuntu 11.04, now
that I have just upgraded to the new distribution of Ubuntu (11.10), I
get the following error message while QGIS loads, and after it has
finished loading, I can't access the plugin installer (only plugin
manager and already installed plugins).

You may help me if you would know in which direction I could look to handle it.

Thanks you
Florent Beck

Here the error message: (as I got it in french I'll translate french
parts into english within brackets after each line)
Error message : >>>
Impossible de charger PyQGIS. [Can't load PyQGIS.]
Le support python va être désactivé. [Python support will be desabled
(or deactivated ?).]

Traceback (most recent call last):
  File "", line 1, in
RuntimeError: the PyQt4.QtCore module is version 1 but the qgis.core
module requires version -1

Version de Python : [Python's version :]
2.7.2+ (default, Oct  4 2011, 20:29:37)
[GCC 4.6.1]

Version de QGIS :  [QGIS's version :]
1.7.1-Wroclaw 'Wroclaw', exported

Chemin vers Python : [Path to Python :]
['/usr/share/qgis/python',
'/home/forest/.qgis/python',
'/home/forest/.qgis/python/plugins',
'/usr/share/qgis/python/plugins',
'/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-2.8-gtk2-unicode']

<<< END of the error message.
Thanks in advance for each kind of help.
Florent