Plug-in error messages overwrite header

I appreciate this may have to be fixed by editing the plug-in somehow but I am using a popular plug-in called BP registration options.
If you are not logged-in then the plugin outputs an error message whenever you try and access a community area.
The error messages write straight across the drop down community header area, and I expect this is not the only plug-in to have this unfortunate effect.
Any suggestions on getting around this would be appreciated.