When I activate the AlphaOmega plugin on one site, I get this message:
Notice: A session had already been started - ignoring session_start() in /home/www/www/wp-content/plugins/alphaomega-captcha-anti-spam/alphaomega-captcha-and-anti-spam.php on line 82
I tried deactivating all the other plugins, and still got this message. I tried a different theme, and still got this message. I have another site which works fine with this plugin, so there's something different with this site.
Any ideas what it could be conflicting with?