You appear to be using PHP 5.2.0 or lower. PHP 5.2 reached end of life status (by the PHP developers not us) on 6 January 2011.
While we do support PHP 5.1+, we need PHP 5.1.x or PHP 5.2.0 to be compiled with the "enable-memory-limit" option, which some PHP installs don't have. This is not documented, which I'll correct, but we won't be changing the actual code given the PHP versions here are really really old and insecure.
While we do support PHP 5.1+, we need PHP 5.1.x or PHP 5.2.0 to be compiled with the "enable-memory-limit" option, which some PHP installs don't have. This is not documented, which I'll correct, but we won't be changing the actual code given the PHP versions here are really really old and insecure.