Plugin bloqueou meu acesso ao site…

Instalei o plugin do Climatempo no site e aconteceu isso:

Warning: session_start(): Cannot send session cookie – headers already sent by (output started at /home/integ369/public_html/wp-content/plugins/previsao-do-tempo/class/WidgetSeloClimatempo.class.php:1) in /home/integ369/public_html/wp-content/plugins/stats-counter/wpadm-class-wp.php on line 9

Warning: session_start(): Cannot send session cache limiter – headers already sent (output started at /home/integ369/public_html/wp-content/plugins/previsao-do-tempo/class/WidgetSeloClimatempo.class.php:1) in /home/integ369/public_html/wp-content/plugins/stats-counter/wpadm-class-wp.php on line 9

Warning: Cannot modify header information – headers already sent by (output started at /home/integ369/public_html/wp-content/plugins/previsao-do-tempo/class/WidgetSeloClimatempo.class.php:1) in /home/integ369/public_html/wp-content/plugins/wp-super-cache/wp-cache-phase2.php on line 62

Warning: Cannot modify header information – headers already sent by (output started at /home/integ369/public_html/wp-content/plugins/previsao-do-tempo/class/WidgetSeloClimatempo.class.php:1) in /home/integ369/public_html/wp-login.php on line 425

Warning: Cannot modify header information – headers already sent by (output started at /home/integ369/public_html/wp-content/plugins/previsao-do-tempo/class/WidgetSeloClimatempo.class.php:1) in /home/integ369/public_html/wp-login.php on line 438

Alguém tem alguma ideia de como reverter essa situação? Preciso acessar a area administrativa para fazer atualizações e não consigo.

Site: http://www.integracaocultural.com