For assembly instructions, you’ve got two problems in your statement. One, you don’t have an ampersand (&) separating the title_li argument from the exclude argument. Second, you are using single quote around the whole argument list, but also using single quote inside the argument list. To be honest, I don’t know how WP deals with quoting in such a case. PHP in general is pretty flexible, maybe you just want double quotes:
<?php wp_list_pages(“depth=1&title_li=’,’&exclude=67”); ?>