Problem with Time Since and Link Manager

I installed the Time Since plug-in yesterday and had no problems. Now, something has cropped up.

Everything displays fine on my site, but when I click on the Links button in WordPress Admin, I get this:

Warning: Cannot modify header information - headers already sent by (output started at /../../public_html/wordpress/wp-content/plugins/timesince.php:100) in /../../public_html/wordpress/wp-admin/link-manager.php on line 563

Warning: Cannot modify header information - headers already sent by (output started at /../../public_html/wordpress/wp-content/plugins/timesince.php:100) in /../../public_html/wordpress/wp-admin/link-manager.php on line 564

Which is rather surprising, as Time Since shouldn’t be called at all in link-manager.php. I understand what the error means (I have a pretty fair knowledge of PHP) but I don’t understand why it’s showing up. The rest of page loads up just fine and I haven’t gotten the error on any other part of the Admin.

There’s more.

When I click Add Link, the error doesn’t show up. But when I go through the motions of adding a link, and click the Add Link button, I get the following error:

Warning: Cannot modify header information - headers already sent by (output started at /../../public_html/wordpress/wp-content/plugins/timesince.php:100) in /../../public_html/wordpress/wp-admin/link-manager.php on line 214

With no other output to the screen, save for a link to the support forums. The links are added just fine and show up on my site. Any thoughts? I’m using WordPress 1.2.1 with the blog in the root directory, rather than the ./wordpress/ directory.

Thanks,
Michael