Hi!
First off, move wp_reset_postdata(); right under the endforeach; in your related posts loop.. that should fix the error with the incorrect ID.
Secondly.. there doesn’t seem to be a default archive link for posts if you don’t include a date or category tag (like http://www.demo.com/2012/). I honestly cant think of a smooth way to solve this the way it’s set up at the moment.. If I where you I’d either rethink it all or id create categories thats named the same as the companies but with a permalink of something like companyname-cat and assign the posts to them as well. That way you could just put this for the readmore link:
<?php
$cat = get_category_by_slug($post->slug.'-cat');
$catlink = get_category_link($cat->term_id);
?>
<a href="<?php echo $catlink; ?>">View all</a>
then you can check in archive.php if it’s trying to display a category with
if(is_cat()){
//the archive is displaying posts from a category
}
If this solution doesn’t work you could create a custom taxonomy and assign it to the posts (besides categories and tags) and use them instead and change the functions accordingly..
<?php
$cat = get_term_by('slug, '$post->slug.'-cat', 'your-taxonomy-slugname');
$catlink = get_category_link($cat->term_id);
?>
<a href="<?php echo $catlink; ?>">View all</a>
and:
if(is_tax()){
//the archive is displaying a term from a taxoonomy
}
