“Warning: Unknown modifier”

Hi all-

Last night on my blog I started getting some very strnage errors. I have things set up so that when you click “Comments” at the end of the post, the comment window pops up separately. Now if you enter a comment in this pop-up window, clicking the Send button gets you this very odd error message:

Warning: Unknown modifier ‘1’ in /home/comics/public_html/wp-includes/functions.php on line 1348

Warning: Unknown modifier ‘1’ in /home/comics/public_html/wp-includes/functions.php on line 1349

[snip]

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The comments <i>do</i> appear properly on the blog; however, because of the error messages, many users are assuming that there is an error (duh) and posting comments multiple times. Can anyone tell me what may have caused this? The weird thing is that I wasn’t mucking about with any code last night, so I don’t understand what might have caused this to happen. The first time I noticed this happening, I had just done something a little odd. I had accidentally erased a legitimate comment while I was in the midst of purging some comment spam, so I went back and used the original name and text to repost that legitimate comment. But I can’t imagine how doing that would have caused this! Any help anyone can offer would be, um, helpful.

jf