WordPress MU

This was working a few weeks ago, but now when I try to add a user to my blog, I get a message in my email with the following line:

Please click the folowing link to activate your user account:
%s

Obviously the %s should be a link, but for some reason it's not.

Any ideas?

FWIW, here are lines 33 and 34 of my /wp-admin/user-new.php file...not sure if it's correct, but it's definitely not sending anything other than "%s":

Please click the folowing link to activate your user account:
%%s" ), get_bloginfo('name'), site_url(), wp_specialchars( $_REQUEST[ 'role' ] ) );

"This was working a few weeks ago"

Then what changed? And yes, adding a plugin woudl do it.

Very strange...suddenly it just started working again. I literally hadn't changed anything except for a few css colors when this happened, and the only plugin that has been activated is the Dynamic Content Gallery, so it wasn't a plugin.

Not sure what made it work again...weird.