Please try using this CVS snapshot:

  http://snaps.php.net/php4-STABLE-latest.tar.gz
 
For Windows:
 
  http://snaps.php.net/win32/php4-win32-STABLE-latest.zip

..and configure PHP with --enable debug and get us a proper backtrace (with GDB command 'bt')

with php-4.3.7dev './configure' 
'--with-aolserver=/usr/local/aolserver/' '--with-pgsql' 
'--enable-debug'  
 
----output console---- 
[New Thread 1088641968 (LWP 14525)] 
[New Thread 1088711600 (LWP 14526)] 
 
Program received signal SIGSEGV, Segmentation fault. 
[Switching to Thread 1088641968 (LWP 14525)] 
0x40c138e1 in execute (op_array=0x864b078, 
tsrm_ls=0x80c76c8) 
    at /root/php4-STABLE-200404150030/Zend/zend_execute.c:1266 
1266                                    
zend_fetch_var_address(EX(opline), EX(Ts), BP_VAR_W 
TSRMLS_CC); 
(gdb) i r 
eax            0x80c76c8        135034568 
ecx            0x810b050        135311440 
edx            0x864b078        140816504 
ebx            0x40c5ce3c       1086705212 
esp            0x40e25fb0       0x40e25fb0 
ebp            0x40e30a68       0x40e30a68 
esi            0x40e5d030       1088802864 
edi            0x40e5d030       1088802864 
eip            0x40c138e1       0x40c138e1 
eflags         0x210207 2163207 
cs             0x73     115 
ss             0x7b     123 
ds             0x7b     123 
es             0x7b     123 
fs             0x0      0 
gs             0x33     51 
(gdb) bt 
#0  0x40c138e1 in execute (op_array=0x864b078, 
tsrm_ls=0x80c76c8) 
    at /root/php4-STABLE-200404150030/Zend/zend_execute.c:1266 
#1  0x40c18d53 in execute (op_array=0x864f258, 
tsrm_ls=0x80c76c8) 
    at /root/php4-STABLE-200404150030/Zend/zend_execute.c:2200 
#2  0x40c18d53 in execute (op_array=0x864a0e8, 
tsrm_ls=0x80c76c8) 
    at /root/php4-STABLE-200404150030/Zend/zend_execute.c:2200 
#3  0x40c05cf0 in zend_execute_scripts (type=8, 
tsrm_ls=0x80c76c8, retval=Variable "retval" is not 
available. 
) 
    at /root/php4-STABLE-200404150030/Zend/zend.c:886 
#4  0x40bd3204 in php_execute_script 
(primary_file=0x40e35800, 
    tsrm_ls=0x80c76c8) 
at /root/php4-STABLE-200404150030/main/main.c:1731 
#5  0x40c1b609 in php_ns_module_main (tsrm_ls=Variable 
"tsrm_ls" is not available. 
) 
    at /root/php4-STABLE-200404150030/sapi/aolserver/aolserver.c:419 
#6  0x40c1b985 in php_ns_request_handler 
(context=0x80c7698, conn=Variable "conn" is not available. 
) 
    at /root/php4-STABLE-200404150030/sapi/aolserver/aolserver.c:503 
#7  0x4003a152 in Ns_ConnRunRequest () 
from /usr/local/aolserver/lib/libnsd.so 
#8  0x4003b9d6 in ConnRun () 
from /usr/local/aolserver/lib/libnsd.so 
#9  0x4003b660 in NsConnThread () 
from /usr/local/aolserver/lib/libnsd.so 
#10 0x40067c18 in NsThreadMain () 
from /usr/local/aolserver/lib/libnsthread.so 
#11 0x4006914a in ThreadMain () 
from /usr/local/aolserver/lib/libnsthread.so 
#12 0x401227d3 in start_thread () 
from /lib/tls/libpthread.so.0 
#13 0x4023ab4a in clone () from /lib/tls/libc.so.6

From the sapi/aolserver/README: "Note that there might be thread-safety issues with thread-unsafe libraries/extensions.  Test thoroughly before you put anything into production." (this is pretty much impossible to tell what might be going wrong. Just use Apache 1.3.29 and you're fine.)

erm.. it's okay. 
probably, I still with aolserver. (it's for openacs, so a 
compulsary) 
later i'll give you more information.