My php.ini memory limit is set to "-1" and I'm trying to install a RSS builder (https://github.com/thujohn/rss-l4) using Laravel 4 and I'm getting the following error. Any ideas?

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Updating dependencies (including require-dev)

• Installing thujohn/rss (dev-master df80a7d)
  Downloading: 100%
  PHP Fatal error: Uncaught exception 'ErrorException' with message 'proc_open(): fork failed - Cannot allocate memory' in phar:///usr/local/bin/composer/vendor/symfony/console/Symfony/Component/Console/Application.php:975
  Stack trace:
  #0 [internal function]: Composer\Util\ErrorHandler::handle(2, 'proc_open(): fo...', 'phar:///usr/loc...', 975, Array)
  Added ErrorException handler. #1 phar:///usr/local/bin/composer/vendor/symfony/console/Symfony/Component/Console/Application.php(975): proc_open('stty -a | grep ...', Array, NULL, NULL, NULL, Array)
  Edited src/Composer/Downloader/ZipDownloader.php via GitHub #2 phar:///usr/local/bin/composer/vendor/symfony/console/Symfony/Component/Console/Application.php(853): Symfony\Component\Console\Application->getSttyColumns()
  Implement PEAR support. #3 phar:///usr/local/bin/composer/vendor/symfony/console/Symfony/Component/Console/Application.php(818): Symfony\Component\Console\Application->getTerminalDimensions()
  Edited README.md via GitHub #4 phar:///usr/local/bin/composer/vendor/symfony/console/Symfony/Component/Console/Application.php(752): Symfony\Component\Console\Application->getTerminalWidth()
  Edited bin/composer via GitHub #5 phar:///usr/local/bin/com in phar:///usr/local/bin/composer/vendor/symfony/console/Symfony/Component/Console/Application.php on line 975

Fatal error: Uncaught exception 'ErrorException' with message 'proc_open(): fork failed - Cannot allocate memory' in phar:///usr/local/bin/composer/vendor/symfony/console/Symfony/Component/Console/Application.php:975
Stack trace:
#0 [internal function]: Composer\Util\ErrorHandler::handle(2, 'proc_open(): fo...', 'phar:///usr/loc...', 975, Array)
#1 phar:///usr/local/bin/composer/vendor/symfony/console/Symfony/Component/Console/Application.php(975): proc_open('stty -a | grep ...', Array, NULL, NULL, NULL, Array)
#2 phar:///usr/local/bin/composer/vendor/symfony/console/Symfony/Component/Console/Application.php(853): Symfony\Component\Console\Application->getSttyColumns()
#3 phar:///usr/local/bin/composer/vendor/symfony/console/Symfony/Component/Console/Application.php(818): Symfony\Component\Console\Application->getTerminalDimensions()
#4 phar:///usr/local/bin/composer/vendor/symfony/console/Symfony/Component/Console/Application.php(752): Symfony\Component\Console\Application->getTerminalWidth()
#5 phar:///usr/local/bin/com in phar:///usr/local/bin/composer/vendor/symfony/console/Symfony/Component/Console/Application.php on line 975