Thread:Extension talk:OpenID/Call to a member function getAssociation() on a non-object in ...Consumer.php on line 945/reply (5)

Actually no, this issue is caused by openbase_dir. You assume that you can write to /tmp, in today's hosting market this is no always the case. I suggest in the future you use sys_get_temp_dir.

The easy work around is to set:

$wgOpenIDServerStorePath

and

$wgOpenIDConsumerStorePath

to a dir that you do have write perms to.