Problem with navigation links in the Add Media window

My problem is not with the upload function itself, but the Add Media window that opens up from any of the edit pages. The initial window that pops up when clicking on the Add Media button works fine and I can upload my file without issue. The problem arises when I try to use any of the other links in that Add Media window (From Computer, From URL, Gallery, Media Library, or even the link to try the Browser Uploader). In IE, clicking on any of these links returns the error “The address is not valid” and in any other browser, nothing happens.

Upon closer inspection, I found that the links look like this:
http:/?post_id=14&tab=gallery (the Gallery tab)

I’ve disabled all plugins just in case it was one of them, but that didn’t solve the problem. I also found this other thread which seems to be the same problem, but unfortunately the solution reached there is not applicable as the server I’m on is already running Apache.

Any help would be appreciated.