@ Morgan
I have check your problem.
But i could not reconstruct this url problem. - http://finakonsten.dinstudio.se = ok.
Except when the follow was entered. - finakonsten.dinstudio.se !!!!!
I suspect this is exactly your problem. 
This is the flynax regex from function isUrl
Code:
Only registered members can view the code.
In action you can see it here - LINK
Look at the matched urls and you can see your problem and a other error. 
Is this a url? - http://finakonsten.dinstudio No!
The same with my regex.
Code:
Only registered members can view the code.
In action you can see it here - LINK
Open includes/classes/rlValid.class.php
Go to - function isUrl($url)
and change the follow part
PHP Code:
Only registered members can view the code.
with this part
PHP Code:
Only registered members can view the code.
The same problem is in function isDomain($domain)
change the follow part
PHP Code:
Only registered members can view the code.
In action = LINK
with this part
PHP Code:
Only registered members can view the code.
In action = LINK
Perhaps it also solves your url-problem with http://finakonsten.dinstudio.se or better
finakonsten.dinstudio.se 
Please test it...