Fatal G2 error

Here's the error from G2: Error (ERROR_MISSING_OBJECT) : Parent 6900 path walkaboutlove

in modules/core/classes/helpers/GalleryFileSystemEntityHelper_simple.class at line 98 (GalleryCoreApi::error)
in modules/core/classes/GalleryCoreApi.class at line 1952 (GalleryFileSystemEntityHelper_simple::fetchChildIdByPathComponent)
in modules/core/classes/helpers/GalleryFileSystemEntityHelper_simple.class at line 53 (GalleryCoreApi::fetchChildIdByPathComponent)
in modules/core/classes/GalleryCoreApi.class at line 1901 (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 56 (RewriteUrlGenerator::_onLoad)
in init.inc at line 166 (ModRewriteUrlGenerator::initNavigation)
in modules/core/classes/GalleryEmbed.class at line 129
in /var/www/vhosts/digitaldonkey.de/httpdocs/wp-content/plugins/wpg2/wpg2embed.inc at line 47 (GalleryEmbed::init)
in /var/www/vhosts/digitaldonkey.de/httpdocs/wp-content/plugins/wpg2/wpg2embed.inc at line 95
in /var/www/vhosts/digitaldonkey.de/httpdocs/wp-content/plugins/wpg2/wpg2template.inc at line 46
in ??? at line 0
in /var/www/vhosts/digitaldonkey.de/httpdocs/wp-includes/plugin.php at line 339
in /var/www/vhosts/digitaldonkey.de/httpdocs/wp-includes/template-loader.php at line 7
in /var/www/vhosts/digitaldonkey.de/httpdocs/wp-blog-header.php at line 16
in /var/www/vhosts/digitaldonkey.de/httpdocs/index.php at line 21