I Just wanted to say that I'm having the same problems with the instance maps not working. Sometimes they load, sometimes they don't. Sometimes it just shows the skull icons for the bosses and the star for the entrance and nothing else behind it and then clicking on other instance maps does nothing.
Sometimes when opening a map it looks scrambled like this http://img230.imageshack.us/img230/5165/wowscrnshot092807082543wm5.jpg
I get no errors.
Typing /print Cartographer:GetModule("InstanceMaps") gives me