Hi,
Not sure if you seen this already but some people might find it helpful. The guide is for Fedora but the first part of it works for any OS 
http://fedoramagazine.org/how-to-get-firefox-looking-right-on-a-high-dpi-display-and-fedora/
This might help understand the various config options so that you can customize Firefox the way you want. http://kb.mozillazine.org/About:config_entries
There seem to be superfluous characters in your URL. They show as <b></b> in the URL.
I removed them from FF’s address line and then it works.
But trying to post that corrected URL here in a post failes!. It shown <strong>/strong> annd reving them does not heelp. They are added immedialtly
Assuming the : is wrong in there, I replaced it with %3A. That seems to make a workable URL: