User Sync Error after upgrade

I just updated to beta 6 and get the following error message in 'admin/user/gallery/users/sync' when I click the sync link for a user:

Error in function 'gallery_handle_request()' (gallery_base.inc:164):

    * Error (ERROR_MISSING_OBJECT) : Parent 7 path users
          o in modules/core/classes/helpers/GalleryFileSystemEntityHelper_simple.class at line 98 (gallerycoreapi::error)
          o in modules/core/classes/GalleryCoreApi.class at line 1845 (galleryfilesystementityhelper_simple::fetchchildidbypathcomponent)
          o in modules/core/classes/helpers/GalleryFileSystemEntityHelper_simple.class at line 53 (gallerycoreapi::fetchchildidbypathcomponent)
          o in modules/core/classes/GalleryCoreApi.class at line 1796 (galleryfilesystementityhelper_simple::fetchitemidbypath)
          o in modules/rewrite/classes/RewriteSimpleHelper.class at line 45 (gallerycoreapi::fetchitemidbypath)
          o in ??? at line 0 (rewritesimplehelper::loaditemidfrompath)
          o in modules/rewrite/classes/RewriteUrlGenerator.class at line 103
          o in modules/rewrite/classes/parsers/modrewrite/ModRewriteUrlGenerator.class at line 43 (modrewriteurlgenerator::_onload)
          o in init.inc at line 147 (modrewriteurlgenerator::initnavigation)
          o in main.php at line 180
          o in main.php at line 94
          o in modules/core/classes/GalleryEmbed.class at line 179
          o in /home/gaiatrav/public_html/new/sites/all/modules/gallery/gallery_base.inc at line 146 (galleryembed::handlerequest)
          o in /home/gaiatrav/public_html/new/sites/all/modules/gallery/gallery.module at line 383
          o in ??? at line 0
          o in /home/gaiatrav/public_html/new/includes/menu.inc at line 418
          o in /home/gaiatrav/public_html/new/index.php at line 15

this is what I get in the gallery settings install page ('admin/settings/gallery/install'):

    *

      A serious error has occured. This can happen due to an incorrect configuration or a bug in the gallery module. If you plan to submit a bug report to the issue queue at drupal.org consider to include the pre-generated report file.
    * Error in function 'gallery_handle_request()' (gallery_base.inc:164):
          o Error (ERROR_MISSING_OBJECT) : Parent 7 path install
                + in modules/core/classes/helpers/GalleryFileSystemEntityHelper_simple.class at line 98 (gallerycoreapi::error)
                + in modules/core/classes/GalleryCoreApi.class at line 1845 (galleryfilesystementityhelper_simple::fetchchildidbypathcomponent)
                + in modules/core/classes/helpers/GalleryFileSystemEntityHelper_simple.class at line 53 (gallerycoreapi::fetchchildidbypathcomponent)
                + in modules/core/classes/GalleryCoreApi.class at line 1796 (galleryfilesystementityhelper_simple::fetchitemidbypath)
                + in modules/rewrite/classes/RewriteSimpleHelper.class at line 45 (gallerycoreapi::fetchitemidbypath)
                + in ??? at line 0 (rewritesimplehelper::loaditemidfrompath)
                + in modules/rewrite/classes/RewriteUrlGenerator.class at line 103
                + in modules/rewrite/classes/parsers/modrewrite/ModRewriteUrlGenerator.class at line 43 (modrewriteurlgenerator::_onload)
                + in init.inc at line 147 (modrewriteurlgenerator::initnavigation)
                + in main.php at line 180
                + in main.php at line 94
                + in modules/core/classes/GalleryEmbed.class at line 179
                + in /home/gaiatrav/public_html/new/sites/all/modules/gallery/gallery_base.inc at line 146 (galleryembed::handlerequest)
                + in /home/gaiatrav/public_html/new/sites/all/modules/gallery/gallery.module at line 383
                + in ??? at line 0
                + in /home/gaiatrav/public_html/new/includes/menu.inc at line 418
                + in /home/gaiatrav/public_html/new/index.php at line 15

Has anyone experienced the same before?
I did a complete deinstall of the module and still get the error once i try to go through the install routine.

Thanks for any hint you can give me.