Are you sure you put that line in the right place? This hack cannot cause a parse error, since all it does is add another "AND" requirement to the query that gets all the emails to be sent to when a new reply is made.
Without my hack, the query looks like this:
PHP Code:
$useremails=$DB_site->query("SELECT user.*
FROM subscribethread,user
WHERE subscribethread.threadid='$threadid'
AND subscribethread.userid=user.userid
AND user.userid<>'$userid'
AND user.lastactivity>'$lastposttime[dateline]'");
After my hack, the query looks like this:
PHP Code:
$useremails=$DB_site->query("SELECT user.*
FROM subscribethread,user
WHERE subscribethread.threadid='$threadid'
AND subscribethread.userid=user.userid
AND user.userid<>'$userid'
AND user.usergroupid NOT IN (1,3,4,8,17)
AND user.lastactivity>'$lastposttime[dateline]'");
Go and install the hack again, and make sure that you are putting that extra line in the right place in functions.php - this hack does NOT and can NOT interfere with any other hack. It just adds another requirement to that specific query.