Please do following step to update the Travelo theme.
1. Download latest version from themeforest.
2. Activate another theme in administrator in your website.
3. Delete Travelo theme in your website via ftp.
4. Install latest version in your website and activate it.
5. Install/update required plugins in Appearance -> Tools menu or Travelo -> Tools menu.
Please confirm you did not change theme files in your website before updating.