Fatal G2 error

Here's the error from G2: Error (ERROR_COLLISION)

in modules/core/classes/GallerySession.class at line 712 (GalleryCoreApi::error)
in modules/core/classes/GallerySession.class at line 322 (GallerySession::_acquireNewPersistentSession)
in modules/core/classes/GallerySession.class at line 513 (GallerySession::start)
in modules/core/classes/GallerySession.class at line 285 (GallerySession::regenerate)
in modules/core/classes/Gallery.class at line 294 (GallerySession::init)
in init.inc at line 144 (Gallery::initSession)
in modules/core/classes/GalleryEmbed.class at line 99
in /usr/local/share/wordpress/wp-content/plugins/wpg2/wpg2embed.inc at line 47 (GalleryEmbed::init)
in /usr/local/share/wordpress/wp-content/plugins/wpg2/wpg2embed.inc at line 95
in /usr/local/share/wordpress/wp-content/plugins/wpg2/wpg2template.inc at line 46
in ??? at line 0
in /usr/local/share/wordpress/wp-includes/class-wp-hook.php at line 286
in /usr/local/share/wordpress/wp-includes/class-wp-hook.php at line 310 (WP_Hook::apply_filters)
in /usr/local/share/wordpress/wp-includes/plugin.php at line 465 (WP_Hook::do_action)
in /usr/local/share/wordpress/wp-includes/template-loader.php at line 13
in /usr/local/share/wordpress/wp-blog-header.php at line 19
in /usr/local/share/wordpress/index.php at line 17