Sorry for the terse note but I am in the stress of finishing
a project and have no time to produce a reproducing script.
The code it's too complicated. [hope to come back later
with a sample]

configure line as per phpinfo():
 '--enable-versioning' '--with-mysql' '--with-pgsql'
'--disable-pic' '--with-dom' '--with-ldap=/usr'
 '--enable-trans-sid' '--enable-wddx' '--with-shmop'         '--with-mm' '--enable-memory-limit' '--with-sablot'
--with-mnogosearch' '--enable-sockets' '--with-zlib' '--enable-debug'

Here are the log notice and bt:

[Fri Mar 16 12:35:45 2001] [notice] child pid 27350 exit signal Segmentation fault (11)
[Fri Mar 16 12:36:05 2001] [notice] caught SIGTERM, shutting down
[Fri Mar 16 12:36:48 2001]  Script:  '/usr/local/cvsdevel/php/a/htdocs/index.php'
---------------------------------------
zend_execute_API.c(261) : Block 0x08159370 status:
zend_variables.c(62) : Actual location (location was relayed)
Beginning:      Cached (allocated on var.c:475, 13 bytes)
      End:      OK
---------------------------------------
FATAL:  erealloc():  Unable to allocate 1515878401 bytes

Program received signal SIGSEGV, Segmentation fault.
0x40089ac1 in __kill () from /lib/libc.so.6
(gdb) bt
#0  0x40089ac1 in __kill () from /lib/libc.so.6
#1  0x401c86e1 in objects () at zend_alloc.c:535
#2  0x40292025 in php_ob_allocate () at output.c:226
#3  0x402917fc in php_ob_append (text=0x0, text_length=1515870810) at output.c:260
#4  0x40291956 in php_b_body_write (str=0x0, str_length=1515870810) at output.c:337
#5  0x4029134a in objects () at output.c:53
#6  0x401f7e26 in php_body_write_wrapper (str=0x0, str_length=1515870810) at main.c:682
#7  0x401e22db in objects () at zend.c:116
#8  0x401e225c in objects () at zend.c:116
#9  0x401e1d04 in objects () at zend_variables.c:147
#10 0x401e247c in objects () at zend.c:116
#11 0x401e232c in objects () at zend.c:116
#12 0x401e1f8b in print_hash (ht=0x8159544, indent=12) at zend.c:107
#13 0x401e23e2 in objects () at zend.c:116
#14 0x401e232c in objects () at zend.c:116
#15 0x401e1f8b in print_hash (ht=0x815a2b4, indent=4) at zend.c:107
#16 0x401e2462 in objects () at zend.c:116
#17 0x401e232c in objects () at zend.c:116
#18 0x40254d30 in objects () at basic_functions.c:1815
#19 0x401d3f8a in objects () at ./zend_execute.c:853
#20 0x401d4168 in objects () at ./zend_execute.c:853
#21 0x401d4168 in objects () at ./zend_execute.c:853
#22 0x401d4168 in objects () at ./zend_execute.c:853
#23 0x401e31a4 in objects () at zend.c:260
#24 0x401f8a7f in objects () at main.c:1128
#25 0x401f4a7c in objects () at sapi_apache.c:98
#26 0x401f5595 in objects () at mod_php4.c:439
#27 0x401f55d6 in objects () at mod_php4.c:439
#28 0x8076669 in ap_invoke_handler ()
#29 0x808c05f in process_request_internal ()
#30 0x808c0d2 in ap_process_request ()
#31 0x8082c76 in child_main ()
#32 0x8082e55 in make_child ()
#33 0x8082fd6 in startup_children ()
#34 0x808365c in standalone_main ()
#35 0x8083eac in main ()
#36 0x40083a8e in __libc_start_main () at ../sysdeps/generic/libc-start.c:93

I make use of nested output buffering and I guess it's
a problem somewhere there (str=0x0) with a null pointer :(

ciao

-- teodor