Duplicate key error when activating

I got the following error when activating Woocommerce. Is ikt anything to worry about?

WordPress database error Can't write; duplicate key in table '#sql-664_8ff48' for query 
					ALTER TABLE <code>wp_22_wc_download_log</code>
					ADD CONSTRAINT <code>fk_wc_download_log_permission_id</code>
					FOREIGN KEY (<code>permission_id</code>)
					REFERENCES <code>wp_22_woocommerce_downloadable_product_permissions</code> (<code>permission_id</code>) ON DELETE CASCADE;
				 made by activate_plugin, do_action('activate_woocommerce/woocommerce.php'), WP_Hook->do_action, WP_Hook->apply_filters, WC_Install::install, WC_Install::create_tables