admin blacklists self by manually marking comments as spam

This module has allowed us to accept anonymous comments when we otherwise would not, so it's been invaluable. But...

we've had an avalache of (very different) spam in the 24 hours, and I've been logged in as admin and been manually "mark as spam" these comments to train the filters. Then,

1) in one browser (Opera), I'm logged in as admin and can still do work, but
2) in another browser (FF), where I'm not logged in, I get a 403 (I think) on my home page*, yet
3) in same other browser (FF), I can view other pages on the site!

* Your IP address (X.X.X.X) was recently used to post spam to this website. For this reason, you are currently not allowed to post new content. If you believe this is in error, please contact the site administrator.

I also gave this task/priv (mark as spam) to another user on the website, and that account has experienced the same behavior.

How do I un-blacklist us? What did we do wrong in the first place? Thanks for any help!