"The fantastic lxml wrapper for libxml2 is required by inkex.py and therefore this extension. Please download and install the latest version from http://cheeseshop.python.org/pypi/lxml/, or install it through your package manager by a command like: sudo apt-get install python-lxml"
To fix this try:
Steps to work around the known issue of python-based extensions not working with the official Inkscape 0.48.2 package on OS X 10.7 Lion:
Prerequisites:
- unmodified version of Inkscape 0.48.2 installed
- alternative text editor is available (see earlier comment)
- quit all open Inkscape windows
1) Open a new Finder window and browse to the directory where you installed Inkscape to (most likely '/Applications').
2) select 'Inkscape', open the context menu (with the right mouse button
or 'Ctrl+mouse button' for single-button mouse or 'Ctrl+tap' with the
trackpad) and choose the entry 'Show Package Contents'
3) within the package contents, browse to 'Contents > Resources > bin'
4) in 'Contents > Resources > bin' open the file 'inkscape' in a
plain-text editor (use drag&drop for example, or 'Open with…' from
the context menu)
5) once you have the file (a shell script) open in the text editor, go to line 32.
The content of line 32 is:
export VERSIONER_PYTHON_PREFER_32_BIT=yes
6) above line 32, insert a new line with this text:
export VERSIONER_PYTHON_VERSION=2.6
7) save the changes (make sure that no (hidden) file extension is added)
8) test Inkscape: launch the app and use for example 'Extensions > Render > Gear…' as test
If all went well, all python-based extensions (those from the menu 'Extensions' as well as those used for input/output extensions to support other file formats) will work now as expected.
Link:https://answers.launchpad.net/inkscape/+question/194132#comment-4