[grb123]

I haven't installed this yet, but I can't find those lines either (perhaps it's a version thing), however in index.php the following lines show the logged in users:

eval("\$loggedinusers = \"".gettemplate('forumhome_loggedinusers')."\"; ");

So I guess you could add it after that, but make sure you correct the code you're adding as well as it is changed from $onlineusers to $loggedinusers.

You don't even need this as it looks like all it does is show who's currently in chat which is useful but not essential for the chat to run.

It does appear though that the person who wrote this hack no longer uses it on his site.