I've had no shortage of headaches after updating the rules module yesterday.
used some of the suggestions above and ended up with the following situation:
a) site is asking me to rebuild access permissions but fails with the following message (see file 1)
b) if I try to see if updates were completed I get the following message (see file 2).
This is what I see in the log when trying to rebuild access permissions:
Notice: Undefined index: controller class in entity_get_controller() (line 7748 of /home/content/02/7225902/html/includes/common.inc)
My site is not showing many of the posts for anyone not signed in, and this is a problem for us.