I have the same problem. Just updated to wordpress 3.5. The “add media” pop up box comes up with posts just not when I want to add an image to a page. I don’t know much about code & I have no idea if I’m with dreamhost or not.
Also- I don’t want to hi-jack a thread but I also don’t want to post a new topic about this & have someone tell me I should have done a search on this first. So here I am…if I’m supposed to be somewhere else, please let me know.