After much hassle with the isp, (who ask for a printscreen from the scanned pc to their abuse department by e-mail after they cut the connection

Along with a reinstall of both laptop and pc I installed and recommended they use firefox as a less vulnerable browser.
Now comes the problem.
In IE everything is fine.
In Firefox however certain spaces are replaced by  
I checked around and it simply is the code for non-breaking space. I haven't found a reason why it should show up.
Now I think it's just because of how the people made the page but I wonder if I can do anything about it so they don't have to switch back to IE for that.
Example Page.
http://www.duiven.net/verkoop/?page=view&id=239