DBG does not save sessions. Therefore seems that it is impossible to keep the sessions variables. Or just a stupid mistake as ususal. Anyway I have a hard time.
Machine is Win 2000 advances server
PHPEd latest trial version

dump od phpinfo:
dbg
DBG php debugger, version 2.14.9, Copyright 2001, 2002, 2003 Dmitri Dmitrienko, http://www.nusphere.com/dbg

Version 2.14.9
Linked as a shared library.
Dbg security enabled.
Profiler compiled, enabled

Directive Local Value Master Value
debugger.enable_session_cookie On On
debugger.enabled On On
debugger.fail_silently On On
debugger.hosts_allow protected value protected value
debugger.hosts_deny protected value protected value
debugger.ignore_nops Off Off
debugger.JIT_enabled On On
debugger.JIT_host clienthost clienthost
debugger.JIT_level 3 3
debugger.JIT_port 7869 7869
debugger.ports protected value protected value
debugger.profiler_enabled On On
debugger.session_nocache On On
debugger.timeout_seconds 300 300

Any help is highly appreciated

Sorry for the post.
But anyway the question remains.

If I explicitly give a session id like

session_id(blah);

and then call

session_start()
it works fine. But if does not recognise the default session IDs

Where is a problem. PHP.ini, dbg, apache or my stupidity
thanks for reading

Session ID is passed back to the client via Cookie. If you have cookies disabled the ID is missed everytime you do submit or click on a link.
Read appropriate manual topics in the php manual and feedbacks on the php.net site.

Hi Dima

Thanks for suggestion. I found out exactly the same. The new session_id solve it. But the people said I quote;

"
Just for info, session_start() blocks if another PHP using the same session is still running in background. It seems it's waiting the other PHP to finish... and sometimes it can be a problem. Create 2 different sessions by setting 2 different names : session_name() solve the problem
_____end quote______

Does it mean that DBG runs its own session and therefore the clients' sessions are blocked?

Thanks