OK I found what the bug seems to be.
basically I had set my time offset to be '2' in the config-inc file
And a positive value there seems to make the whose online thing fall over, or atleast not show you anyone online other than yourself. A negative value I guess would work for 10mins plus however many hours negative offset. So ony a zero offset really works.
Why cos sometime wwthreads uses just the time() function, ie like when updating your w3t_Online table and other times like when clearing the w3t_Online table which it does before it shows it, it will use the get_date() function which is time+offset.
So the if you don't have a zero offset then make this change to the online.php file:
// $Outdated = $html -> get_date(); //previous code
// $Outdated = $Outdated - 600; //previous code
$Outdated = time() - 600; // added by Dan5
Find the two lines I have commeted out, and comment them out and then add my line.
Let me know if this causes any side effects but I don't see why it should be a problem it seems ok on my BB.
http://www.fatdogexchange.com/bb/wwwthreads.php
Regards
Dan