I've had the same problems as noted in 2187, 3168, and 3292, where Apache will not start with the PHP module setup to load, if mysql is compiled in.
I discovered that when you run httpd -X, it segfaults.
I took the core and ran a backtrace:
#0  0x4033f6a8 in ?? ()
#1  0x400f53fa in _IO_new_file_close_it (fp=0x809dea8) at fileops.c:136
#2  0x400f127d in _IO_new_fclose (fp=0x809dea8) at iofclose.c:50
#3  0x4022af5f in php3_init_config () at configuration-parser.y:226
#4  0x40221777 in php3_config_ini_startup () at main.c:947
#5  0x40222292 in php3_module_startup () at main.c:1231
#6  0x4021fe2a in php3_create_dir ()
#7  0x8053fd4 in ap_single_module_configure ()
#8  0x804f14d in ap_get_server_built ()
#9  0x8052f44 in ap_clear_module_list ()
#10 0x805350c in ap_handle_command ()
#11 0x8053558 in ap_srm_command_loop ()
#12 0x80538c7 in ap_process_resource_config ()
#13 0x8053f44 in ap_read_config ()
#14 0x805ae47 in ap_child_terminate ()
#15 0x805b4fb in main ()
#16 0x400b81eb in __libc_start_main (main=0x805b290 <main>, argc=2,
    argv=0xbffffd44, init=0x804e684 <_init>, fini=0x80794ec <_fini>,
    rtld_fini=0x4000a610 <_dl_fini>, stack_end=0xbffffd3c)
    at ../sysdeps/generic/libc-start.c:90
This is with Apache 1.3.9, RedHat distributed apache-1.3.9-8.i386.rpm
Incidentally, it does NOT happen with RedHat's build 4 (from the 6.1 distro).  So apache-1.3.9-4.i386.rpm will work fine, this only shows if you use updated RPMs.