My b2evolution Version: Not Entered

Hi guys!

I've read a lot about the permalinks but i still have a problem with my blog.
http://blog.nechan.at

I'd like to have permalinks like http://blog.nechan.at/posttitle

I've set the correct settings but if i click on one of the post titles ill always get an 404 error page.
Until i figured out the problem my blog still runs with permalinks like /indexphp/blogtitle

Can someone give me any advice how to solve that problem?
I tried to edit the .htacces file (the last 4 lines) but if i delete the comment (#) chars i cant access the blog anymore.

Thanks in advance!