Did you check on Drupal.org?
http://drupal.org/node/481758 http://drupal.org/node/1171756 -- this one suggests that PHP 5.2.x is the culprit.
Nancy Injustice anywhere is a threat to justice everywhere. -- Dr. Martin L. King, Jr.
From: Prothero William
This is very frustrating. I am trying to install a virgin version of Drupal 7.12. I am getting an error message:
Fatal error: Call to undefined function field_attach_load() in /home/sbjazz/public_html/includes/entity.inc on line 320