The page headers have already been sent out in /usr/home/e2064006/html/nucleus/libs/globalfunctions.php line 16. This could cause Nucleus not to work in the expected way.
Usually, this is caused by spaces or newlines at the end of the config.php file, at the end of the language file or at the end of a plugin file. Please check this and try again.
If you don't want to see this error message again, without solving the problem, set $CONF['alertOnHeadersSent'] in globalfunctions.php to 0