added these lines to httpd.conf after installing php4 from source:

#begin php4
LoadModule php4_module /usr/local/php4/php-4.4.7/libs/libphp4.so
AddModule mod_php4.c
#end php4

then i restarted my apache server but it won't start up now


-bash-3.00# /etc/init.d/httpd restart
Stopping httpd:                                            [  OK  ]
Starting httpd: Syntax error on line 28 of /etc/httpd/conf.d/php.conf:
Cannot load /usr/local/php4/php-4.4.7/libs/libphp4.so into server: /usr/local/php4/php-4.4.7/libs/libphp4.so: undefined symbol: empty_string
                                                           [FAILED]


what does this error mean? how do i fix it?