apache不能解释php

已经安装了php，MYSQL，
apache曾经是可以运行php的，
但现在在web中浏览php文件的时候，
总是提示要将php页面下载下来。

我尝试过在httpd.conf加入php模块：
LoadModule php_module        modules/mod_php.so
LoadModule php3_module       modules/mod_php3.so
LoadModule perl_module       modules/mod_perl.so

AddModule mod_php.c
AddModule mod_php3.c
AddModule mod_perl.c
但restart的httpd的时候出错

我也尝试过加入：
AddType application/x-httpd-php .php
AddType application/x-httpd-php3 .php3
AddType application/x-httpd-php-source .phps

但还是不行，apache还是不可以解释php
请问什么原因？
谢谢。

看看apache的日志

I have resolved this problem.
Since apache can't run php, it means apache can't realize that when i request a php file, it should hand it over to the php engine to parse the file. As a result, it just to send the file i requested.
Here are what i done(in httpd.conf):

1) Load php module, add "LoadModule php4_module /usr/local/apache/libexec/libphp4.so". Obviously, libphp4.so must exists in the libexec directory;
2) Add php module. add this directive: "AddModule php4_module.c";
3) Add file type:
    AddType application/x-httpd-php .php
    AddType application/x-httpd-php3 .php3
    AddType application/x-httpd-php-source .phps
4) restart apache server:
    /etc/rc.d/init.d/httpd restart

[quote:65c8726331="barble"]I have resolved this problem.
Since apache can't run php, it means apache can't realize that when i request a php file, it should hand it over to the php engine to parse the file. As a result, it just to send the file i requested.
Here are what i done(in httpd.conf):

1) Load php module, add "LoadModule php4_module /usr/local/apache/libexec/libphp4.so". Obviously, libphp4.so must exists in the libexec directory;
2) Add php module. add this directive: "AddModule php4_module.c";
3) Add file type:
    AddType application/x-httpd-php .php
    AddType application/x-httpd-php3 .php3
    AddType application/x-httpd-php-source .phps
4) restart apache server:
    /etc/rc.d/init.d/httpd restart[/quote]


AddModule php4_module.c我插入这段话后.重启出错啊

出的什么错 ？？