aegir error

Generated config Drush configuration file
Changed permissions of /var/aegir/.drush/mysite.swingon.in.alias.drushrc.php to 440
Command dispatch complete
Peak memory usage was 16.96 MB
Loaded alias @mysite.swingon.in from file /var/aegir/.drush/mysite.swingon.in.alias.drushrc.php
Loading drushrc "/var/aegir/platforms/commons-7.x-3.8/sites/mysite.swingon.in/drushrc.php" into "site" scope.
exec(): Unable to fork [hostname -f] environment.inc:750
Backend invoke: php /usr/share/php/drush/drush.php --backend=2 @mysite.swingon.in provision-verify 2>&1
php /usr/share/php/drush/drush.php --backend=2 @mysite.swingon.in provision-verify 2>&1
proc_open(): fork failed - Cannot allocate memory backend.inc:372
Invalid argument supplied for foreach() hosting_package.module:332
array_key_exists() expects parameter 2 to be array, null given hosting_package.instance.inc:54
array_key_exists() expects parameter 2 to be array, null given hosting_package.instance.inc:54
array_key_exists() expects parameter 2 to be array, null given hosting_package.instance.inc:54
array_key_exists() expects parameter 2 to be array, null given hosting_package.instance.inc:54
array_key_exists() expects parameter 2 to be array, null given hosting_package.instance.inc:54