to this:
add_action(“comment_post”, “comment_not_read”, 10, 2);

And that gets rid of the error message. (this fix was based on http://wordpress.org/support/topic/298291)

However, I noticed that unapproved comments still show up as “unread” even though they are not live on the site.

Maybe my change caused that? Or (more likely) it was like that before?

I think your plugin might be incompatible with the current version of WordPress? Or am I doing something wrong? I did a fresh install of WP 2.8.2 (latest as of today) but I keep getting these errors:

Warning: Missing argument 2 for comment_not_read() in /home/mysite/public_html/wp/wp-content/plugins/mark-as-read/storage.php on line 31

Warning: Cannot modify header information – headers already sent by (output started at /home/mysite/public_html/wp/wp-content/plugins/mark-as-read/storage.php:31) in /home/mysite/public_html/wp/wp-includes/pluggable.php on line 865

I get this error regardless of whether or not is pasted into the theme.

Looking at the code in storage.php, the offending variable seems to be $approved:

//insert the post that has not been read with COMMENT type, will be fired after a comment post
function comment_not_read($comment_id, $approved) {
$comment = get_comment($comment_id);

insert_not_read($comment->comment_post_ID, “comment”);
}

Let me know if you have any ideas on this. Thank you!

@baron: Thanks!