I'm afraid this doesn't work. 
I'm trying to get fanfiction.net to work (using 3.43-7 on WinXP). 
Let's use your example fanfiction.net one to work.
The url: www.fanfiction.net/s/4573177/1/
All settings default, except for Scan Rules, which now only has the following
rule: +www.fanfiction.net/s/*
If I add www.fanfiction.net/* it'll grab the whole site, and I only want the
links of the other chapters which would be /4573177/2/ /4573177/3/ and so on
and so forth (the 'title after the chapter number is unecessary). 

The same goes for changing expert rules (up and down? grabs the whole site, as
does up, actually...). Is there some way of going sideways... hmm...