Original answer
For Python 2 on Ubuntu 11.10, using upstart, install the python plugin for uWSGI with apt-get install uwsgi-plugin-python and if you’re using an ini file to configure your uWSGI app, then add plugins = python to the [uwsgi] section and it should solve this problem.
Edit: Updated for Python 3 and Ubuntu 17.10
For Python 3 on Ubuntu 17.10, using systemd, install the python plugin for uWSGI with apt-get install uwsgi-plugin-python3 and if you’re using an ini file to configure your uWSGI app, then add plugins = python to the [uwsgi] section and it should solve this problem.
For more information on getting started with python/uWSGI apps, including how to configure them using an ini file then please take a look at this handy guide