Thanks, but it didn't work at all (I'd get a new message thou - Access denied ).
My guess is that it's something strange with the Punbo component and I think I'll ask there too.
My coding skills isn't much to brag about, but I think yours are so...
The link to a certain users profile page is http://mydomain/index.php?option=com_punbo&Itemid=36&task=profile&id=3 where id, of course, is the id of the user.
The Joomla/Punbo-thing is a little different from the Punbb-thing, I suppose.
Well, I suck. Thanks for your time.