When I installed the iSite 6.x-1.0-rc2 version on my FreeBSD, pair.com server, and clicked to configure, I got the Fatal error: allowed memory size exhausted. I got the answer to fix this from drupal:

Fatal error: Allowed memory size of X bytes exhausted (tried to allocate Y bytes)...
http://drupal.org/node/76156

The answers that worked for me was to:

# ini_set('memory_limit', '48M'); in your sites/default/settings.php file
# php_value memory_limit 48M in your .htaccess file in the Drupal root

I don't have access to php.ini on this server.
I initially trided 16M, 32M .... finally 48M worked....
Changed in both places at the same time...
I clicked my back button to re run so when it finally ran, there were
duplicate errors from attempts to add the same new records in db.
I ignored these and it now seems to work

You may want to make these changes in these two files before distribution, if others
report this as an error.

This Package looks to be a most impressive extension of Drupal. Thanks
-MaineBob