[Boofo]

To make it work for vb 4.1.12, you need to do the following:

In the xml file, change this line:

$vbulletin->templatecache['whosonlinebit'] = str_replace($find, $find . $add, $vbulletin->templatecache['whosonlinebit']);

to this:

$vbulletin->templatecache['whosonline'] = str_replace($find, $find . $add, $vbulletin->templatecache['whosonline']);

Let me know if that fixes it for you.