Errores en PhpBB3

[SEXMONITOR]

Hola:
Acabo de instalar un foro phpbb3 y me da alguns errores.
Una vez q estoy dentro del panel de admin y realizo cambios en el foro,los cambios q realizo se hacen efectivos,pero me sale errores en la web como este:


[phpBB Debug] PHP Notice: in file /includes/utf/utf_normalizer.php on line 136: nfc(./../includes/utf/data/utf_nfc_qc.php): failed to open stream: No such file or directory
[phpBB Debug] PHP Notice: in file /includes/utf/utf_normalizer.php on line 136: nfc(): Failed opening './../includes/utf/data/utf_nfc_qc.php' for inclusion (include_path='.:/usr/local/php4/share/pear')
[phpBB Debug] PHP Notice: in file /includes/utf/utf_normalizer.php on line 142: nfc(./../includes/utf/data/utf_canonical_decomp.php): failed to open stream: No such file or directory
[phpBB Debug] PHP Notice: in file /includes/utf/utf_normalizer.php on line 142: nfc(): Failed opening './../includes/utf/data/utf_canonical_decomp.php' for inclusion (include_path='.:/usr/local/php4/share/pear')
[phpBB Debug] PHP Notice: in file /includes/utf/utf_normalizer.php on line 253: recompose(./../includes/utf/data/utf_normalizer_common.php): failed to open stream: No such file or directory
[phpBB Debug] PHP Notice: in file /includes/utf/utf_normalizer.php on line 253: recompose(): Failed opening './../includes/utf/data/utf_normalizer_common.php' for inclusion (include_path='.:/usr/local/php4/share/pear')
[phpBB Debug] PHP Notice: in file /includes/utf/utf_normalizer.php on line 260: recompose(./../includes/utf/data/utf_canonical_comp.php): failed to open stream: No such file or directory
[phpBB Debug] PHP Notice: in file /includes/utf/utf_normalizer.php on line 260: recompose(): Failed opening './../includes/utf/data/utf_canonical_comp.php' for inclusion (include_path='.:/usr/local/php4/share/pear')
[phpBB Debug] PHP Notice: in file /adm/index.php on line 149: Cannot modify header information - headers already sent by (output started at /includes/functions.php:2956)
[phpBB Debug] PHP Notice: in file /adm/index.php on line 151: Cannot modify header information - headers already sent by (output started at /includes/functions.php:2956)
[phpBB Debug] PHP Notice: in file /adm/index.php on line 152: Cannot modify header information - headers already sent by (output started at /includes/functions.php:2956)
[phpBB Debug] PHP Notice: in file /adm/index.php on line 153: Cannot modify header information - headers already sent by (output started at /includes/functions.php:2956)

Lo mismo sucede si publico un mensaje en el foro.El mensaje se publica,pero aparecen errores de ese tipo.
Como lo puedo solucionar?
Gracias.