[eluser]davidbehler[/eluser]
Might work.
But you said, that the url without any parameters works, right? And as soon as you add controller/function it doesn't work anymore and you get those errors. This usually means there's something wrong with your htaccess file or the uri_protocol you use, but since you removed the file and tried all protocols, I got no idea what else might be wrong.
What hoster are you using? Have you googled for known problems with CI and your hoster?