Sample script:
<?php
   print "hello world!";
?>

apache-1.3.27 configured with:
./configure --enable-module=unique_id --enable-module=rewrite --enable-module=usertrack --enable-module=so

PHP-4.2.3 configured with:
./configure --with-pgsql --with-interbase --with-mysql=/usr/local/mysql/ --with-apxs=/www/bin/apxs --with-openssl --enable-debug

gdb backtrace:
Program received signal SIGSEGV, Segmentation fault.
0x4020f466 in ?? ()
(gdb) bt
#0  0x4020f466 in ?? ()
#1  0x4020b4e2 in ?? ()
#2  0x401f92a3 in ?? ()
#3  0x401d1181 in ?? ()
#4  0x401f9993 in ?? ()
#5  0x4020d4c7 in ?? ()
#6  0x40207a30 in ?? ()
#7  0x402089c8 in ?? ()
#8  0x40208a52 in ?? ()
#9  0x808dd69 in ap_invoke_handler (r=0x81bafdc) at http_config.c:538
#10 0x80a38cf in process_request_internal (r=0x81bafdc) at http_request.c:1312
#11 0x80a3d36 in ap_internal_redirect (new_uri=0x81bafb4 "/index.php", 
    r=0x81ba354) at http_request.c:1440
#12 0x8074336 in handle_dir (r=0x81ba354) at mod_dir.c:174
#13 0x808dd69 in ap_invoke_handler (r=0x81ba354) at http_config.c:538
#14 0x80a38cf in process_request_internal (r=0x81ba354) at http_request.c:1312
#15 0x80a393a in ap_process_request (r=0x81ba354) at http_request.c:1328
#16 0x809a150 in child_main (child_num_arg=0) at http_main.c:4629
#17 0x809a315 in make_child (s=0x816acdc, slot=0, now=1038414204)
    at http_main.c:4744
#18 0x809a496 in startup_children (number_to_start=1) at http_main.c:4826
#19 0x809ab2d in standalone_main (argc=4, argv=0xbffff8d4) at http_main.c:5134
#20 0x809b39c in main (argc=4, argv=0xbffff8d4) at http_main.c:5482
#21 0x400892e7 in __libc_start_main () from /lib/libc.so.6

/www/logs/error_log:
...[notice] child pid 18177 exit signal Segmentation fault (11)

-----------------

If you'd like me to try different configs, etc, let me know.

Regards
Henry