I just installed apache 1.3.27 over apache2.x so that I could install phorum. After installing apache, I went through configuring php to work with apache1.x. PHP installed OK, but when I try to start apache, I get the following error:

Syntax error line 205 of /usr/local/apache/conf/httpd.conf:
Cannot load libexec/libphp4.so into server:
/usr/local/apache/libexec/libphp4.so:
undefined symbol: core_globals
httpd cannot be started

On line 205 in httpd.conf is the LoadModule command inserted by the php installation:

LoadModule php4_module libexec/libphp4.so

Here are the params for my apache install:
./configure --prefix=/usr/local/apache --enable-modules=so

and for PHP:

./configure --with-apxs=/usr/local/apache/bin/apxs --with-mysql

If anyone can shed some light on this error, I would be very grateful. Thanks in advance.

I have finally fixed this problem. What I ended up doing was removing the pho src directory (the one with the ./configure in it) and untarred it again. This way, any leftover compiled stuff that was configured for the other version was removed. This did the trick!