Thank you for this bug report. To properly diagnose the problem, we
need a short but complete example script to be able to reproduce
this bug ourselves. 

A proper reproducing script starts with <?php and ends with ?>,
is max. 10-20 lines long and does not require any external 
resources such as databases, etc.

If possible, make the script source available online and provide
an URL to it here. Try to avoid embedding huge scripts into the report.

We really need some reproduce script and/or gdb backtrace.
Please reopen the report when you have it.

Ok. here I created bgd from the script's which I unable to run . In the url I created space between www and rest url .

First is webmail I created 2 files core and bgd 
Core: www. technofor.us/belenkas/php_webmail.core
gdb : www. technofor.us/belenkas/gdb_mail

Callendar ( it required zend ) IPB 
Core: www. technofor.us/belenkas/php_calendar.core
gdb:  www. technofor.us/belenkas/calendrar_gbd

One more program Tunez it's wont run too with the same error ... 
Core: www. technofor.us/belenkas/tunez_php.core
gdb:  www. technofor.us/belenkas/tunez_gdb

And I downgraded php back to the 4.3.11 becose zend not compatible with 4.4 . Im not sure how to create the script so I provide just gdb and core files . Core files I created in the SSH the typed php index.php . If need some mroe info let me know . 
Regards

Now please turn off ZendOptimizer and rebuild PHP with --enable-debug. 
Your backtraces doesn't contain any useful information, because you didn't read http://bugs.php.net/bugs-generating-backtrace.php.

Ok. I just installed the 4.4.0RC1 again with --enable-debug and disabled zend optimizer if Im correct in php.ini file ? I comented out this lines :
;[Zend]
;zend_optimizer.optimization_level=15
;zend_extension_manager.optimizer=/usr/local/Zend/lib/Optimizer-2.5.10
;zend_extension_manager.optimizer_ts=/usr/local/Zend/lib/Optimizer_TS-2.5.10
;
;zend_optimizer.version=2.5.10
;zend_extension=/usr/local/Zend/lib/ZendExtensionManager.so
;zend_extension_ts=/usr/local/Zend/lib/ZendExtensionManager_TS.so

Stoped and started apache after that .

And created new gdb and core files

Squire webmail 
Core :  www technofor.us/belenkas/php_webmail.core
gdb : www technofor.us/belenkas/gdb_mail

Tunez
Core: www technofor.us/belenkas/tunez_php.core
gdb : www technofor.us/belenkas/tunez_gdb

Callendar
Core: www technofor.us/belenkas/calendar.core
gdb:  www technofor.us/belenkas/calendrar_gbd

Regards

Obviously there is going something wrong, but it would really help us if you could come up with a short reproducable script. It seems related to user defined sessions, but can you recreate one of the backtrace where you have the session module compiled in statically (and not as a shared object)? (You also don't have to put the core files online, as they are useles without the system they were generated on).

Hmm Im not sure how to create reproducible script . But If I shortened the mailbox.php script to this lines :
<?php
/**
 * Find out the base URI to set cookies.
 */
define('SM_PATH','../');
if (!function_exists('sqm_baseuri')){
    require_once(SM_PATH . 'functions/display_messages.php');
}
?>
And did gdb it's will give me this output :

(gdb) bt
#0  0x080ca91e in _zval_ptr_dtor (zval_ptr=0x28a63928) at /usr/home/bender/php-4.4.0RC1/Zend/zend_execute_API.c:287
#1  0x080a493e in var_destroy (var_hashx=0x1) at /usr/home/bender/php-4.4.0RC1/ext/standard/var_unserializer.c:132
#2  0x28a5ce9b in ps_srlzr_decode_php () from /usr/local/lib/php/20020429/session.so
#3  0x28a5d1ed in php_session_decode () from /usr/local/lib/php/20020429/session.so
#4  0x28a5d522 in php_session_initialize () from /usr/local/lib/php/20020429/session.so
#5  0x28a5ee15 in php_session_start () from /usr/local/lib/php/20020429/session.so
#6  0x28a604e0 in zif_session_start () from /usr/local/lib/php/20020429/session.so
#7  0x080e3f92 in execute (op_array=0x81f5300) at /usr/home/bender/php-4.4.0RC1/Zend/zend_execute.c:1671
#8  0x080e1bc0 in execute (op_array=0x81ccb0c) at /usr/home/bender/php-4.4.0RC1/Zend/zend_execute.c:1715
#9  0x080e2484 in execute (op_array=0x81cc00c) at /usr/home/bender/php-4.4.0RC1/Zend/zend_execute.c:2257
#10 0x080e2484 in execute (op_array=0x81c8d8c) at /usr/home/bender/php-4.4.0RC1/Zend/zend_execute.c:2257
#11 0x080e2484 in execute (op_array=0x81c8b0c) at /usr/home/bender/php-4.4.0RC1/Zend/zend_execute.c:2257
#12 0x080d3023 in zend_execute_scripts (type=8, retval=0x0, file_count=3) at /usr/home/bender/php-4.4.0RC1/Zend/zend.c:938
#13 0x080ac4b8 in php_execute_script (primary_file=0xbfbfebbc) at /usr/home/bender/php-4.4.0RC1/main/main.c:1751
#14 0x080eb34d in main (argc=2, argv=0xbfbfec3c) at /usr/home/bender/php-4.4.0RC1/sapi/cli/php_cli.c:828

After that I tryed to run display_messages.php but it don't crashes and don't give any gbd . 
Maybe I can give access to my server for you and you will better check what's wrong ? If this gdb dosen't help too much ... 
Regards

And next compile session extension statically into PHP.
(--enable-session without the =shared part!)

And REALLY come up with a SHORT reproducing script without any include/require, etc. external crap we have no access to.

No feedback was provided for this bug for over a week, so it is
being suspended automatically. If you are able to provide the
information that was originally requested, please do so and change
the status of the bug back to "Open".

I had the same bug.

It's now solved by using this:
portupgrade -Rf php4-session