When I try to execute a twitter action (post a tweet) from a triggered rule, the action is (apparently) not executed and I get the following warning displayed on screen:
warning: Parameter 1 to rules_core_action_execute() expected to be a reference, value given in /srv/www/html/sites/all/modules/rules/rules/rules.module on line 603.
... no message is posted to twitter. A spot of debug code tells me the warning happens when the rules_element_invoke() function does call_user_func_array() for the above function with the twitter_actions_set_status_action action as parameter.
I expect it may be because I run PHP 5.3. I would fix it, but I'm not quite sure where to start.