It appears that the error you are facing is because the 'site-builder' tool requires a 'sites-config.yaml' file to function properly. This configuration file specifies package information for the Sui blockchain and other necessary operational details.. Ensure that this configuration file is located in one of the default locations (e.g., '$XDG_HOME/walrus/' or '$HOME/.config/walrus/') or specify the path explicitly with the '--config' flag. Additionally, make sure that your Sui wallet is correctly configured with the proper RPC settings for either Testnet or Mainnet. You might also want to check if your Walrus and binary versions are up-to-date as incompatible versions can lead to similar issues. For more details, you can refer to the setup instructions provided in the official Walrus documentation here: https://docs.walrus.site/usage/setup.html.