Drupal 7.22

Steps to reproduce:
1. Log out of site
2. Attempt to log in at mysite/saml_login

Expected results: Successful login
Actual results: Message to user - "We're sorry. There was a problem. The issue has been logged for the administrator." Message in log as stated below.

When I was trying to test the login, I would get the log message "A user attempted to login using this module but there was a problem." I found out by instering some debugging statements that this was because the module's implementation of hook_init() was not being called at all (likely due to caching). I've temporarily put a call to that function in simplesamlphp_auth_loginpage() and everything seems to work normally.