The pages now all work, but the code was suspicious and so were my changes.
Yes, in fact your changes result in a loss of the relative linking support. I don't believe dropping this support is the desired way to go (even in the short term). Rather, I think we should address the issue with the internationalized "folder part" of the URL. If a message key is what needs to be in the folder name, then this key needs to be in the URL, too. Localizing the folder name when building the link to be presented will obviously cause failure because then it won't match the canonical folder name (the message key).
I believe Anupriya came up with a better (short term?) solution, see: https://openacs.org/bugtracker/openacs/bug?bug_number=1511 ...
/Ola
