I've never tried it with CBlogin, but I use it on several Joomla 1.5 websites with Joomla SEF turned on and it works fine for me. What problems did you see with Joomla SEF turned on?
Regarding CBlogin - this plugin is triggered by the Joomla Core user event "onLoginFailure" ( see http://docs.joomla.org/Reference:User_Events_for_Plugin_System#5.3.5_onLoginFailure)
so it must be that CB is not using this joomla core user event when a CB login failure occurs.
This is a very complex concept and you made it easy.
Thank you Thank you Thank You
That may be nice but it isn't what this module is. It makes no claim to work with other banner modules and I think it is a little harsh to criticize it for something it doesn't claim to do.