comments link does not show in single.php or sidebar

My third stumper in a month, on different websites.

Suddenly, my comments popup link doesn’t show up. The sentence in the sidebar reads “You can , or trackback to this site” — the words “you can” are generated by the “if” statement so I know comments are indeed enabled, and triggering the right “if” statement to display — but the blank spot before the comma is where it should say “join the discussion” or “not comment” or something. The code is as follows:

<?php comments_popup_link('comment', 'join the discussion',
'join the discussion', 'comments-link', 'not comment, sorry,'); ?>

Likewise, if I put the same code in my single.php, it doesn’t show up. I have found many references to this problem, but not a single solution, other than to be sure and use the if(is_single) which I did, to no avail.

Sure would appreciate any help or ideas on this one. ??