之前碰到过，忘了怎么弄的，这次又碰到了，刚设置WP Keyword Link插件，停用的时候就弹出这个错误了
刚想时下有以下几种解决方法:

1. Blank lines (空白行):

Make sure no blank line after <?php … ?> of the calling php scrīpt.

检查有<?php … ?> 后面没有空白行，特别是include或者require的文件。不少问题是这些空白行导致的。

2. Use exit statement (用exit来解决):

Use exit after header statement seems to help some people

在header后加上exit();

header (“Location: xxx”);

exit();

3. PHP has this annoying problem, if your HTML goes before any PHP code or any header modification before redirecting to certain page, it ll said “Warning: Cannot modify header information – headers already sent by ….” Basically anytime you output to browser, the header is set and cannot be modified. So two ways to get around the problem:

3a. Use Javascrīpt (用Javascrīpt来解决):

<? echo “<scrīpt> self.location( file.php );</scrīpt>”; ?>

Since it s a scrīpt, it won t modify the header until execution of Javascrīpt.

可以用Javascrīpt来代替header。另外需要注意，采用这种方法需要浏览器支持Javascrīpt.

3b. Use output buffering (用输出缓存来解决):—本人用这种方法解决的！已证实可以！

<?php ob_start(); ?>

… HTML codes …

<?php

… PHP codes …

header (“Location: ….”);

ob_end_flush();

?>