CB Login Module works fine. More than likely it's loading a plugin that's causing problems. As you sad UddeIM is causing you errors that is likely the cause since the CB Login Module has a new PM notification which will interact with UddeIM. Yes, you can replace UddeIM with CBs built in private messaging. Simply edit the Private Message System plugin in CB > Plugin Management, change Model to Internal, run the UddeIM Migration (button below Model) then begin the uninstall process of UddeIM (remove its CB plugins first).