Calendar, Permalink Question

Hello,
I’m sorry if this has been answered before, but I have a question regarding the calendar. In order to use it, must my permalink structure be the “ugly” style? This is the only way I can get it to work. I’ve tried the other default permalink options and some of my own which included the post_id and/or the date, yet the calendar links don’t work. It’s only for the individual days though; browsing by month or year still works fine no matter what the permalink structure is. When I view the day (eg. index.php/date/2006/07/12/), I get an Internal Server Error (500). I’m new to WordPress and I’m using the most current version.

Thanks.