For those of you using Haloscan for commenting and currently experiencing a frustrating comment outage on your site, here's a fix:
1) Log into your Haloscan account
2) Click on "Settings"
3) Click on "Beta Features"
4) Scroll down to the heading Spam Filters - Change "Enable Redirect" from YES to NO.
5) Save your changes
Your comments will now work, although it may be a little while before the number of comments entered register on the main site.
Note this will only work for the comments on your own site, not someone else's. They'll have to make the change to their own Haloscan account for your comments on their posts to show up.
I would recommend keeping an eye out for when Haloscan fixes this problem (if ever) so you can change the Spam filter setting back to YES, but this should work in the meantime...