I've got the same problem of a page that loads, then immediately disappears, using OSX 10.5.8 and Safari 4.0.2.. I assume it's a problem with either the Safari CSS and/or something to do with how the JavaScript works.
Then again, it might be a problem with the WebCore library itself, because my usual system (10.6.8) stopped loading webpages AT ALL, which is why I'm running the ancient 10.5.8. I managed to cobble together a system install using another bootable partition and an old installer DMG.
It does display for a second, but I either cannot hit command-period at just the right spot, or Safari for some reason CANNOT stop the page load/javascript/rendering before whatever is causing it to disappear happens.
