Warning: Cannot modify header... 경고창

로칼 서버에서 작업 수정한 파일(write.skin.php등 다수)을 ftp로 제 홈페이지(www.biz-nara.com)main 서버에 전송하고 나서 보니 "글쓰기" 창을 불러 올때 다음과 같은 경고 메세지가 뜹니다.

어디를 손봐야 하는지요?

Warning: Cannot modify header information - headers already sent by (output started at /home/biznara/public_html/bbs/write.php:1) in /home/biznara/public_html/common.php on line 8

Warning: Cannot modify header information - headers already sent by (output started at /home/biznara/public_html/bbs/write.php:1) in /home/biznara/public_html/head.sub.php on line 32

Warning: Cannot modify header information - headers already sent by (output started at /home/biznara/public_html/bbs/write.php:1) in /home/biznara/public_html/head.sub.php on line 34

Warning: Cannot modify header information - headers already sent by (output started at /home/biznara/public_html/bbs/write.php:1) in /home/biznara/public_html/head.sub.php on line 35

Warning: Cannot modify header information - headers already sent by (output started at /home/biznara/public_html/bbs/write.php:1) in /home/biznara/public_html/head.sub.php on line 36

Warning: Cannot modify header information - headers already sent by (output started at /home/biznara/public_html/bbs/write.php:1) in /home/biznara/public_html/head.sub.php on line 37

Warning: Cannot modify header information - headers already sent by (output started at /home/biznara/public_html/bbs/write.php:1) in /home/biznara/public_html/head.sub.php on line 38