PHP crashes frequently (document contains no data in netscape and segmentation fault (11) in error_log). If I try to run the same script again, it usually sucseeds. Script contains no syntax errors.

PHP configure line:
./configure --with-mysql --with-apxs --disable-debug --enable-track-vars --with-gd=/usr

Apache 1.3.12-2 was installed from rh6.2 cd.

php.ini contains these lines:
zend_optimizer.optimization_level=7
zend_extension="/usr/local/Zend/lib/ZendOptimizer.so"

Zend optimizer is RC1-Linux-glibc2.1


(no debugging symbols found)...
(gdb) run -X
Starting program: /usr/sbin/httpd -X

Program received signal SIGSEGV, Segmentation fault.
0x676e6974 in ?? ()
(gdb) bt
#0  0x676e6974 in ?? ()
#1  0x402a1e77 in php_session_track_init () at session.c:387
#2  0x402a1ee4 in _php_session_decode (
    val=0x8109d54 "kasutaja_nr|s:1:\"1\";url|s:22:\"/it/helpdesk/tabel.php\";",     
vallen=54) at session.c:405
#3  0x402a3e6f in php_if_session_decode (ht=1, return_value=0x810c68c, 
    this_ptr=0x0, return_value_used=0) at session.c:1195
#4  0x403c7023 in zend_oe_ex () from /usr/local/Zend/lib/ZendOptimizer.so
#5  0x403bdef3 in zend_oe () from /usr/local/Zend/lib/ZendOptimizer.so
#6  0x40270d27 in php_execute_script (primary_file=0xbffff608) at main.c:1157
#7  0x4026da50 in apache_php_module_main (r=0x80e9e2c, fd=19, 
    display_source_mode=0) at sapi_apache.c:93
#8  0x4026e343 in send_php (r=0x80e9e2c, display_source_mode=0, 
    filename=0x80eb9e4 "/home/httpd/html/kaskkirjad/kaskkirjad.php")
    at mod_php4.c:515
#9  0x4026e384 in send_parsed_php (r=0x80e9e2c) at mod_php4.c:527
#10 0x805345e in ap_invoke_handler () from /usr/local/Zend/lib/ZendOptimizer.so
#11 0x80618fb in ap_some_auth_required ()
   from /usr/local/Zend/lib/ZendOptimizer.so
#12 0x8061958 in ap_process_request ()
   from /usr/local/Zend/lib/ZendOptimizer.so
#13 0x805b940 in ap_child_terminate ()
   from /usr/local/Zend/lib/ZendOptimizer.so
#14 0x805baa7 in ap_child_terminate ()
   from /usr/local/Zend/lib/ZendOptimizer.so
#15 0x805bba8 in ap_child_terminate ()
   from /usr/local/Zend/lib/ZendOptimizer.so
#16 0x805c058 in ap_child_terminate ()
   from /usr/local/Zend/lib/ZendOptimizer.so
#17 0x805c65f in main () from /usr/local/Zend/lib/ZendOptimizer.so
#18 0x400be9cb in __libc_start_main (main=0x805c3e0 <main>, argc=2, 
    argv=0xbffff7e4, init=0x804f014 <_init>, fini=0x807b99c <_fini>, 
    rtld_fini=0x4000ae60 <_dl_fini>, stack_end=0xbffff7dc)
    at ../sysdeps/generic/libc-start.c:92