Ubuntu 9.04 is shipped with four versions of Python:
- 2.4.6 (Zope2 still requires Python 2.4)
- 2.6.2 (default)
Ubuntu's Python team hasn't included my multiprocessing backport for Python 2.4 and 2.5 in Jaunty although Sandro Tosi has created a Debian package. You still have to install it manually from PyPI.
Did you install Python 2.6 yourself before? Make sure you remove it ASAP!
At first I couldn't figure out why lots of Python based applications were broken. It was a major issue for me because Ubuntu uses Python in lots of places. Then it occured to me that it may be related to my previous installation of Python 2.6. Ubuntu 8.04 didn't use Python 2.6 but 9.04 uses 2.6 as default Python for its apps. And /usr/local has precedence over /usr. Once it was gone everything worked again.
In order to wipe your own installation of Python from your hard disk you have to remove
- /usr/local/lib/python2.6 (except for an empty site-packages directory)