Drupal distributions like Open Atrium and Drupal Commons consist of many modules, already preconfigured and installed. During the installation process of such distributions you can encounter several problems related to your server like 'memory limit error' and 'time execution limit'. These are caused by a complex configuration and calculations being performed during the installation of these packages.
To secure yourself from such sad interruptions and to install everything quickly and smoothly you should do the following:
Before beginning installation of some Drupal distribution open install.php file in your text editor and at the beginning (after ) add these two strings:
set_time_limit(0); ini_set('memory_limit', '256M');
and save your file. By adding these two strings we disabled php execution time limit and ensured that our script will get 256 Megabytes of RAM, of course, we could set it as 128M, but 256M is more reliable, no one knows how much resources would your distribution require during the installation. Note: these settings are for the installation process only, not for your system!
After saving your changes you can freely go and enjoy the installation process. When you finished, don't forget to delete 'install.php' file for security reasons. Hope this small lifehack will save your nerves.