Hi,
I am using RH7.1, gcc 2.96, apache 1.3.19 & php 4.0.5. I 
compiled it from source using this config line:
./configure --prefix=/usr --with-config-file-path=/etc 
--disable-debug --enable-shared 
--enable-inline-optimization --with-apxs=/usr/bin/apxs 
--with-exec-dir=/usr/bin --with-regex=system --with-gd 
--with-jpeg-dir=/usr --with-png --with-zlib --with-db2 
--with-db3 --with-gdbm --enable-debugger 
--enable-magic-quotes --enable-safe-mode --enable-sockets 
--enable-sysvsem --enable-sysvshm --enable-track-vars 
--enable-yp --enable-ftp --enable-wddx --with-mysql=/usr 
--without-oracle --without-oci8 --with-xml --with-openssl 
--enable-dmalloc --enable-pear --enable-bcmath --with-bz2 
--with-tiff-dir=/usr --enable-dbase --with-ttf 
--with-t1lib --with-xpm-dir=/usr --with-ldap 
--with-unixODBC --with-pgsql --with-pspell --enable-posix 
--with-qtdom --with-readline --with-recode 
--with-pdflib=/usr --with-gettext=/usr 
--with-java=/usr/lib/java --with-ming=/usr --disable-pic
The webserver starts normally w/o the php-mdule, but the  
module core dumps. Here's the backtrace:
(gdb) bt
#0  0x4034617f in virtual_file_ex (state=0xbfffd608,
    path=0xbfffe6d0 "/etc/php.ini", verify_path=0) at 
tsrm_virtual_cwd.c:331
#1  0x4029d8b0 in expand_filepath (filepath=0xbfffe6d0 
"/etc/php.ini",
    real_path=0x0) at fopen_wrappers.c:529
#2  0x4029d0e0 in php_fopen_and_set_opened_path 
(path=0xbfffe6d0 "/etc/php.ini",
    mode=0x403600de "r", opened_path=0x4037e904) at 
fopen_wrappers.c:237
#3  0x4029d65e in php_fopen_with_path (filename=0x403600e0 
"php.ini",
    mode=0x403600de "r", path=0x81021a4 ".:/etc", 
opened_path=0x4037e904)
    at fopen_wrappers.c:412
#4  0x4029dcc9 in php_init_config 
(php_ini_path_override=0x0) at php_ini.c:231
#5  0x4029c14f in php_module_startup (sf=0x4037d7e0) at 
main.c:840
#6  0x4029a12a in php_apache_startup 
(sapi_module=0x4037d7e0) at mod_php4.c:259
#7  0x4029a9ea in php_init_handler (s=0x80d8524, 
p=0x80d84fc) at mod_php4.c:729
#8  0x08076f22 in ap_init_modules () at eval.c:41
#9  0x08081098 in main () at eval.c:41
#10 0x400de177 in __libc_start_main (main=0x8080d10 
<main>, argc=4,
    ubp_av=0xbffff8fc, init=0x804eefc <_init>, 
fini=0x80b5d50 <_fini>,
    rtld_fini=0x4000e184 <_dl_fini>, stack_end=0xbffff8ec)
---Type <return> to continue, or q <return> to quit---
    at ../sysdeps/generic/libc-start.c:129
I am using the php.ini-optmized from the php source 
package.