MySQL: What's wrong with this CREATE PROCEDURE statement?

Take out the AS keyword before BEGIN?

This is in the screenshot but you've just added it in an edit. I've checked the 5.x docs and it isn't mentioned at all for CREATE PROCEDURE

There are a few problems. I hope I got them all:

DROP PROCEDURE IF EXISTS CreateTopic;
CREATE PROCEDURE CreateTopic
(
   i_forum_id INT,
   i_user_id INT,
   i_title VARCHAR(255),
   i_language VARCHAR(50),
   i_content TEXT,
   i_stickied TINYINT,
   i_announce TINYINT,
   i_closed TINYINT
)
BEGIN
   DECLARE tid INT;
   INSERT INTO forum_topics (`forum_id`, `user_id`, `title`, `language`)
       VALUES (i_forum_id, i_user_id, i_title, i_language);
   SET tid = LAST_INSERT_ID();
   INSERT INTO forum_posts (`topic_id`, `user_id`, `subject`, `content`) VALUES (tid, i_user_id, i_title, i_content);
   INSERT INTO core_logs (`obj_id`, `user_id`, `type`, `action`) VALUES (tid, i_user_id, 'Topics', 'Topic Created');
END;

It is your first ";" that breaks procedure definition and mysql thinks you are done and treats whatever goes after ";" as another query. You have to use delimiter for stored procedures.

DELIMITER $$
DROP PROCEDURE IF EXISTS CreateTopic$$
CREATE PROCEDURE CreateTopic
(
   i_forum_id INT,
   i_user_id INT,
   i_title VARCHAR(255),
   i_language VARCHAR(50),
   i_content TEXT,
   i_stickied TINYINT,
   i_announce TINYINT,
   i_closed TINYINT
)
BEGIN
   INSERT INTO forum_topics (forum_id, user_id, title, language)
       VALUES (i_forum_id, i_user_id, i_title, i_language);
   SET @tid := LAST_INSERT_ID();
   INSERT INTO forum_posts (topic_id, user_id, subject, content) VALUES (@tid, i_user_id, i_title, i_content);
   INSERT INTO core_logs (obj_id, user_id, type, action) VALUES (@tid, i_user_id, 'Topics', 'Topic Created');
END
$$
DELIMITER ;