I tried installing Ushahidi 2.5 (Cairo) on OSX version 10.8.2 using MAMP 2.1.1. I followed the installation instructions in the README.markdown file that ships with Ushahidi, with the minor modification that I used phpMyAdmin instead of command-line MySQL to create my MySQL database.
Installation worked without a hitch and concluded with a message that said "Installation successful." However, I got a white screen when I visited http://localhost:8888/ushahidi/admin as instructed. I was able to get past the whitescreen error by switching to an older version of PHP in my MAMP preferences. My MAMP ships with PHP 5.2.17 and PHP 5.4.4. When I switched from 5.4.4 to 5.2.17 the login page displayed as expected and I was able to log in.
Sheldon Rampton, New Amsterdam Ideas http://nuams.com