[Zope] only under Opera 6.04

[danielle.d-avout]

Hi, it's me again with my "oversized" problems...
Everytime time I'm asking something , say create an image
the action stops,
and before  I am able access the image_edit_form
I'm getting a blank page with a text  like
http://127.0.0.1:8080/philosophie-africaine/Image.2002-11-12.2458/portal_for
m/image_edit_form?portal_status_message=Image has been created.
I have only this strange behaviour only under OPera 6.04, not Mozilla 1.0
nor explorer 6.0
I start with a fresh instance of Zope Zope-2.5.1-win32, I just update the
CMF core branch to avoid the bug I met before nothing else: same thing!
I didn't find any clues on http://collector.zope.org...
I search on the web
I find something which has similiraties

Jose de Leon opera-users@opera.com
Fri Sep 7 20:46:00 2001

Bug found with streaming content
    To Operat Developers and all concerned:
    There is a "kinda sorta bug" when Opera is served streaming content from
    sites powered by Zope.  This may be present in other html content
delivery
    systems.
    In some cases, the Zope server will send a Content length of 0 at the
start
    of the stream when it should not be sending content length header at
all.
    This will cause Opera to timeout and assume the page has finished.
Symptoms
    are blank pages when the user expected content.
    This is obviously an error with the Zope engine.  We have patched our
local
    copies of Zope.  However, IE and Netscape 4.77 are more forgiving.
Netscape
    6, Mozilla, or Opera is not.
    Might I suggest that Opera be more forgiving with streaming content when
the
    Zope server sends content length of 0 and then sends data?
    Thanks,
        Jose

but the document is rather old and give no clues to patch something.. I'm
not even know whether the pb is related,
a search engine can't help me much my English is too bad to give a name to
what is happening to me,
(in fact I must say as I am a newbie I cant find by myself  "ce qui ne va
pas" and try French keywords in the search engine)