Bogus

If you change the webGUI port to a non-standard port (80, 443) and connect to the webGUI via the ip address, all images an javascript files cannot be found / are falsely linked. I'd recommend to use a full path with port instead of the relative ./file.ext linking.

What browser did you test with? I just tried it with Firefox 3 and IE 7, and it worked fine on a non-standard port; all images were there, and things like traffic graphs etc. still worked. I also can't see any reason why it shouldn't work - with relative links, the browser should use the same address and port that was entered in the address bar.