What you need to do:

First, you need to download it.

Its not just called user.js, its a different one called profile.js in only a couple of versions.
change both of them WHILE FIREFOX IS TURNED OFF!!!!! or it will revert them.
Also put about:config in firefox addressbar while its turned on and change security.checkloaduri to false.
turn off and on then set the path to fileC://tribalwars and make sure that is where you extract the werlt1-4 packs to.

2.0 supports.
It doesnt work if its in anything but tribalwars.

the folder fetches from file:///C:/tribalwars/ (for world 2 &3)
Make sure that when you go into C:\\tribalwars\visual there are all the images for buildings.

Once its in the right place re-check that you set the user.js or profile.js to

user_pref(”capability.policy.policynames”, “localfilelinks”);
user_pref(”capability.policy.localfilelinks.sites” , “[link]“);
user_pref(”capability.policy.localfilelinks.checkloaduri.enabled”, “allAccess”);

Mine worked realy easily 1st time so I cannot see how everyoen else finds it dificult.