Markdown troubles…

When I try to put the following code in a post, my site goes all haywire:
<?php wp_list_cats(‘optioncount=1&sort_column=name’); ?>
I thought Markdown was supposed to fix this, but it doesn’t. Now CodeFilter works, but for some reason, inside the blocks it messes with the css. I guess I have to make a #code css tag to fix that. But, what's the story with Markdown.
I'm using the latest vers of WP (1.2).
Thanks!