<input type="hidden" name="comment_post_ID" value="1" /> **
if you look at your source for differnet permalink pages, you will notice they all have that. at least the 2 posts I looked at have that.
that's not right. That value is dynamically generated -- its the post ID, and every post has a different one.
the corresponding line, inside your theme's comments.php, the way it ought to be is like so:
<input type="hidden" name="comment_post_ID" value="<?php echo $id; ?>" />
note also that the two 2.6.2 themes contain this:
<?php do_action('comment_form', $post->ID); ?>
that hook above, is added before the closing </form>`
--
For more info, and to see what a working comments.php looks like, look inside either of the 2 themes that 'ship' with WP.
If your comment.php looks right, and the unedited stalker theme I looked at has it done right, then you need to disable pretty permalinks and determine why the post_id is being set to 1 for all posts. I say disable permalinks, because the default permalink also uses that, so it might narrow down whether or not its a global problem.
** I edited that to reflect whats really in the source, rather than what FF tells us is in the source. believe it or not, FF likes to "order" things around.