You can bypass the 32 bit Ubuntu 9.10 bug for PyQwt5 mentioned on the Downloading page by building PyQwt5 from source as follows:
You need to have the following packages installed from the Ubuntu package manager: pyqt4-dev-tools python-qt4 python-qt4-dev sip4 python-sip4 python-sip4-dev python-numpy g++ I think that's all ... :-) Of course make sure that any python-qwt5-qt4 Ubuntu supplied package is removed from the system!! Then go to the PyQwt web site, http://pyqwt.sourceforge.net/download.html, download PyQwt-5.2.0.tar.gz, and install for Qt4 according to the instructions at http://pyqwt.sourceforge.net/doc5/installation.html#source-code-installation Unfortunately when doing the source code build the PyQwt5 package gets installed in /usr/lib/python2.6/dist-packages/PyQt4/Qwt5 while the PyQt4 stuff from the package manager is installed in /usr/lib/pymodules/python2.6/PyQt4. Go to /usr/lib/pymodules/python2.6/PyQt4 and do sudo ln -s /usr/lib/python2.6/dist-packages/PyQt4/Qwt5 . and then python calls like import PyQt4.Qwt5 as Qwt will work ...