Problems with python =< 2.5
In file admin_tools/tests.py there is used "with statement". As INSTALL says: "This application requires Python 2.4 or later and Django 1.1.0 or newer". With statement was introduced in python 2.5, but requires importing from future (there is no such in tests.py). Because of that it's impossible to install admin tools (pip, easy_install).
If we're talking about python 2.5, there is no warnings.catch_warnings in python 2.5, but it's not preventing installation (it's only impossible to run tests).