URL Rewrite / Links to gallery2 doesn't work

Hi !

I have the same problem than so lot people with Gallery2 !
I've read a lot of issues about this problem, have tried a lot of things (with .htaccess) : anything is working !
If someone have a solution, it would be great...

The problem :
I've installed a Drupal multisite and Gallery2 in multisite too.

Gallery2 (standalone) is installed in :
/drupal5/sites/all/modules/gallery/gallery2/

The Drupal module Gallery is in :
/drupal5/sites/all/modules/gallery/

And the Gallery2 install for each site :
/drupal5/sites/www.site1.com/modules/gallery2/
/drupal5/sites/www.site2.com/modules/gallery2/

When I arrive to the last step, 'Links to Gallery2 Site Admin sections...', I have this error (my host is 1and1, and [...] is the complete path) :

Security Violation

The action you attempted is not permitted.

Back to the Gallery
Error Detail -
Error (ERROR_PERMISSION_DENIED)

* in modules/core/classes/GalleryView.class at line 168 (gallerycoreapi::error)
* in modules/core/SiteAdmin.inc at line 196 (galleryview::loadview)
* in modules/core/classes/GalleryView.class at line 300 (siteadminview::loadtemplate)
* in main.php at line 441 (siteadminview::doloadtemplate)
* in main.php at line 94
* in modules/core/classes/GalleryEmbed.class at line 179
* in [...]/drupal5/sites/all/modules/gallery/gallery.module at line 215 (galleryembed::handlerequest)
* in ??? at line 0
* in [...]/drupal5/includes/menu.inc at line 418
* in [...]/drupal5/index.php at line 15

System Information
Gallery version 2.2.3
PHP version 4.4.7 cgi
Webserver Apache/1.3.33 (Unix)
Database mysqlt 5.0.41-log
Toolkits Thumbnail, SquareThumb, NetPBM, Gd
Operating system Linux infong 2.4 #1 SMP Thu Jan 13 08:59:31 CET 2005 i686 unknown
Browser Mozilla/5.0 (Windows; U; Windows NT 5.1; fr; rv:1.8.1.7) Gecko/20070914 Firefox/2.0.0.7

My .htaccess is (I am a newbee with appache configuration so I don't really understand what I really do !) :

#
# Apache/PHP/Drupal settings:
#

# Protect files and directories from prying eyes.

Order allow,deny

# Don't show directory listings for URLs which map to a directory.
Options -Indexes

# Follow symbolic links in this directory.
Options +FollowSymLinks

# Customized error messages.
ErrorDocument 404 /index.php

# Set the default handler.
DirectoryIndex index.php

# Override PHP settings. More in sites/default/settings.php
# but the following cannot be changed at runtime.

# PHP 4, Apache 1.

php_value magic_quotes_gpc 0
php_value register_globals 0
php_value session.auto_start 0
php_value mbstring.http_input pass
php_value mbstring.http_output pass
php_value mbstring.encoding_translation 0

# PHP 4, Apache 2.

php_value magic_quotes_gpc 0
php_value register_globals 0
php_value session.auto_start 0
php_value mbstring.http_input pass
php_value mbstring.http_output pass
php_value mbstring.encoding_translation 0

# PHP 5, Apache 1 and 2.

php_value magic_quotes_gpc 0
php_value register_globals 0
php_value session.auto_start 0
php_value mbstring.http_input pass
php_value mbstring.http_output pass
php_value mbstring.encoding_translation 0

# Requires mod_expires to be enabled.

# Enable expirations.
ExpiresActive On
# Cache all files for 2 weeks after access (A).
ExpiresDefault A1209600
# Do not cache dynamically generated pages.
ExpiresByType text/html A1

# Various rewrite rules.

RewriteEngine on
# 1and1 specification
RewriteBase /

# If your site can be accessed both with and without the 'www.' prefix, you
# can use one of the following settings to redirect users to your preferred
# URL, either WITH or WITHOUT the 'www.' prefix. Choose ONLY one option:
#
# To redirect all users to access the site WITH the 'www.' prefix,
# (http://example.com/... will be redirected to http://www.example.com/...)
# adapt and uncomment the following:
# RewriteCond %{HTTP_HOST} ^example\.com$ [NC]
# RewriteRule ^(.*)$ http://www.example.com/$1 [L,R=301]
#
# To redirect all users to access the site WITHOUT the 'www.' prefix,
# (http://www.example.com/... will be redirected to http://example.com/...)
# adapt and uncomment the following:
# RewriteCond %{HTTP_HOST} ^www\.example\.com$ [NC]
# RewriteRule ^(.*)$ http://example.com/$1 [L,R=301]

# Modify the RewriteBase if you are using Drupal in a subdirectory and
# the rewrite rules are not working properly.
RewriteBase /drupal5

# Rewrite old-style URLs of the form 'node.php?id=x'.
#RewriteCond %{REQUEST_FILENAME} !-f
#RewriteCond %{REQUEST_FILENAME} !-d
#RewriteCond %{QUERY_STRING} ^id=([^&]+)$
#RewriteRule node.php index.php?q=node/view/%1 [L]

# Rewrite old-style URLs of the form 'module.php?mod=x'.
#RewriteCond %{REQUEST_FILENAME} !-f
#RewriteCond %{REQUEST_FILENAME} !-d
#RewriteCond %{QUERY_STRING} ^mod=([^&]+)$
#RewriteRule module.php index.php?q=%1 [L]

# Rewrite current-style URLs of the form 'index.php?q=x'.
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule ^(.*)$ index.php?q=$1 [L,QSA]

# $Id: .htaccess,v 1.81.2.2 2007/05/21 01:34:59 drumm Exp $

ThanX for any help !

lor.