Open Publish 2.3 Site Will Not Install

I am running Aegir 1.1 on Ubuntu 10.04 Server. I have created, installed and verified a platform based on Open Publish 2.3 as downloaded from Phase 2. When I try to create a new site, I get these errors from Provision:

Running: /usr/share/drush/drush.php --client_email='me@mysite.com' @www.mysite.com provision-install-backend --backend 2>&1
The external command could not be executed due to an application error.
Undefined offset: 1 backend.inc:163
Undefined variable: output backend.inc:170
The command could not be executed successfully (returned: PHP Fatal error: Allowed memory size of 524288000 bytes exhausted (tried to allocate 45 bytes) in /var/aegir/platforms/openpublish-2.3/includes/file.inc on line 941 , code: 255)
Drush was not able to start (bootstrap) the Drupal database. Hint: This err... (Expand)
Changes made in drush_http_provision_install have been rolled back.

I see that Drush seems to running out of memory, but 500MB or so seems like it should be plenty.

Thanks