Question2Answer query failed:

SELECT qa_posts.postid, qa_posts.categoryid, qa_posts.type, LEFT(qa_posts.type,1) AS basetype, INSTR(qa_posts.type, '_HIDDEN')>0 AS hidden, qa_posts.acount, qa_posts.selchildid, qa_posts.upvotes, qa_posts.downvotes, qa_posts.netvotes, qa_posts.views, qa_posts.hotness, qa_posts.flagcount, BINARY qa_posts.title AS title, BINARY qa_posts.tags AS tags, UNIX_TIMESTAMP(qa_posts.created) AS created, BINARY qa_categories.title AS categoryname, BINARY qa_categories.backpath AS categorybackpath, qa_posts.userid, qa_posts.cookieid, INET_NTOA(qa_posts.createip) AS createip, qa_userpoints.points, qa_users.flags, qa_users.level, BINARY qa_users.email AS email, CONVERT(qa_users.handle USING BINARY) AS handle, qa_users.avatarblobid, qa_users.avatarwidth, qa_users.avatarheight FROM qa_posts LEFT JOIN qa_categories ON qa_categories.categoryid=qa_posts.categoryid LEFT JOIN qa_users ON qa_posts.userid=qa_users.userid LEFT JOIN qa_userpoints ON qa_posts.userid=qa_userpoints.userid JOIN (SELECT postid FROM qa_posts WHERE catidpath3=(SELECT categoryid FROM qa_categories WHERE backpath=_utf8 'tidgauvv_utf8 'Q'0/questions/user-activity' LIMIT 1) AND type=_utf8 '50' ORDER BY qa_posts.created DESC LIMIT #,#) y ON qa_posts.postid=y.postid

Error 1064: You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'Q'0/questions/user-activity' LIMIT 1) AND type=_utf8 '50' ORDER BY qa_posts.crea' at line 1