한글 깨짐 에러 채택완료

안녕하세요.

그누보드4,영카트4,위즈모바일을 사용하고 있습니다만,

head.sub.php에 하기와 같은 에러가 표시되어 모바일만 한글이 깨집니다.

초보라 도대체 뭐가 문제인지 알수가 없네요ㅠㅠ

고수님들 도와주세요~~

--------------에러---------------------

​Warning: Cannot modify header information - headers already sent by (output started at /home/users/1/web/back/extend/down.extend.php:20) in /home/users/1/lolipop.jp-4104f28fbd587c9d/web/m/head.sub.php on line 35

Warning: Cannot modify header information - headers already sent by (output started at /home/users/1/web/back/extend/down.extend.php:20) in /home/users/1/lolipop.jp-4104f28fbd587c9d/web/m/head.sub.php on line 36

Warning: Cannot modify header information - headers already sent by (output started at /home/users/1/web/back/extend/down.extend.php:20) in /home/users/1/lolipop.jp-4104f28fbd587c9d/web/m/head.sub.php on line 37

Warning: Cannot modify header information - headers already sent by (output started at /home/users/1/web/back/extend/down.extend.php:20) in /home/users/1/lolipop.jp-4104f28fbd587c9d/web/m/head.sub.php on line 38

Warning: Cannot modify header information - headers already sent by (output started at /home/users/1/web/back/extend/down.extend.php:20) in /home/users/1/lolipop.jp-4104f28fbd587c9d/web/m/head.sub.php on line 39 

--------------에러 해당소스(35~39행)---------------------------

// 자바스크립트에서 go(-1) 함수를 쓰면 폼값이 사라질때 해당 폼의 상단에 사용하면

// 캐쉬의 내용을 가져옴. 완전한지는 검증되지 않음

header("Content-Type: text/html; charset=$g4[charset]");

$gmnow = gmdate("D, d M Y H:i:s") . " GMT";

header("Expires: 0"); // rfc2616 - Section 14.21

header("Last-Modified: " . $gmnow);

header("Cache-Control: no-store, no-cache, must-revalidate"); // HTTP/1.1

header("Cache-Control: pre-check=0, post-check=0, max-age=0"); // HTTP/1.1

header("Pragma: no-cache"); // HTTP/1.0 

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