I had the same problem as many users of CB 1.2 with the legacy plugin off. I got a part of the CB login module and the message: Direct Access to this location is not allowed.
After upgrading from 1.2.1 to 1.2.2 i had the same problem.
After installation the new mod_cblogin i saw an option in the parameters: CB Plugins Integration. It was set to YES. When i set it to NO! i can disable the legacy plugin without losing the site.
So either the problem is in the cb login module or in a cb plugin which now is not been loaded anymore.
But i think it can be a solution to set CB plugin integration to NO.