Next button doesn’t point to correct url and 404’s

Hi,

I am doing a blog for the local Scout group () and come across a problem with the next page links when the page reaches the number of posts set in: Settings – Reading Settings

I am using the Permalink structure Month and Name and when I try to go to page 2 it points to:

http://24thdorkingscouts.org/page/2/

which 404’s

The link should be:

http://24thdorkingscouts.org/index.php/page/2/

I have reverted back to the original template and this does work so it is template related.

Looking at the code:

if (function_exists('paginate_archives'))
		paginate_archives(array('next_text'=> '»', 'prev_text' => '«')); // If my function exists do it that way otherwise do it the old way.
	else {
		global $wp_query;
		if ( $wp_query->max_num_pages > 1 && !is_singular()) {?>
			<div id="pageNavigation">
				<div id="previousPosts"><?php previous_posts_link(__('&laquo; Previous page'));?></div>
				<div id="nextPosts"><?php next_posts_link(__('Next page &raquo;'));?></div>

			</div><?php
		}
	}?>

And that is as far as I have got with my understanding.

Any help appreciated.

thanks.