You have just upgraded your Capistrano installation to version 2.x, but you didn’t have time to convert your recipes to the newer version.
In order to be able to use your old recipes of Capistrano version 1.x after upgrading, you can use the following (assuming your version 1.x is 1.4.1):
cap _1.4.1_ deploy
or, if you have migrations you want to use:
cap _1.4.1_ deploy_with_migrations