undefined symbol: png_get_error_ptr when starting apache

Hi, after setting up my server for the fifth this night I'm giving up.. Does anybody know, why I'm getting the following error? [root@router bin]# ./apachectl startssl Syntax error on line 239 of /usr/local/apache/1.3.26/conf/httpd.conf: Cannot load /usr/local/apache/current/libexec/libphp4.so into server: /usr/local/apache/current/libexec/libphp4.so: undefined symbol: png_get_error_ptr ./apachectl startssl: httpd could not be started [root@router bin]# httpd.conf: -> line237 <IfDefine SSL> -> line238 LoadModule ssl_module libexec/libssl.so -> line239 LoadModule php4_module libexec/libphp4.so -> line240 </IfDefine> I'm using apache 1.3.26, php 4.2.1, openssl 0.9.6d, mod_ssl 2.8.10, gd 1.8.4, freetype 1.3.1 ans zlib-1.1.4 If I only do a ./apachectl start (without ssl + php) everything works fine. So it must depend on the phpinstall i think. png_get_error_ptr sound like somethink with the libpng libs, but they are already installed. [admin@router src]$ locate libpng /usr/lib/libpng.so.2.1.0.12 /usr/lib/libpng.so.2 /usr/lib/libpng12.so.0 /usr/lib/libpng.so.3.1.2.3 /usr/lib/libpng12.so.0.1.2.3 /usr/lib/libpng.so /usr/local/lib/libpng.so [admin@router src]$ [admin@router src]$ rpm -aq | grep libpng libpng-1.2.3-1 libpng-devel-1.0.12-2 libpng-1.0.12-2 [admin@router src]$ Any ideas ? thank you, Sebastian