It should be created by Q2A. Which version are you using?
Anyway you can run this query
CREATE TABLE `qa_usermetas` (
`userid` int(10) unsigned NOT NULL,
`title` varchar(40) NOT NULL,
`content` varchar(8000) NOT NULL,
PRIMARY KEY (`userid`,`title`),
CONSTRAINT `qa_usermetas_ibfk_1` FOREIGN KEY (`userid`) REFERENCES `qa_users` (`userid`) ON DELETE CASCADE
) ENGINE=InnoDB DEFAULT CHARSET=utf8