Problems with site

I have WordPress 1.5 (strayhorn) installed and something seems terribly wrong. I can post simple posts, but following things do not work:

I can’t Edit/Delete links. I can’t post “Advanced Edited” posts.
Wait a minute. I managed to edit one link, but after that, it says “Link not found.” on every single one of them.
It’s pretty much the same with Categories.
When I create my own post/link/categorie.. it’s given a funky ID# (for example: 144115188075855874)

Sometimes my new posts only end up as a draft.. and when i click on the draft post, it opens a new empty post window.

Does anyone understand this problem? I didn’t know it would be so hard to make wordpress work.

Oh and, here’s the site: http://server.myndak.is/~junior/blog/index.php

Apache 2.x, PHP 4.x MySQL 3.x (i think)
on a Mac OS X Server